English translation Mr and Mrs Smith have just opened a small restaurant.In Order to attract customers, they put a notice in front of the restaurant, which said "means on the house for three days." A foreign student who didn’t know much English happened to pass by the restaurant on the second day.It "Well, here is a restaurant. I am going to have something to eat." he walked toward the restaurant when he saw the notice strange.They even eat dinners on the house!But how can I get up to the top of the house ” he said to himself. He looked around and found a ladder against a tree nearby.He was very glad.But as he reached the top he heard someone shouting at him.“ Hey ,what are you doing up there?” Mr Smith was looking at him angrily and beside him was a policeman. “Doesn’t your notice say ‘Meals on the House for Three Days’?Is it just a joke?” the foreign student answered . On hearing this,both Mr Smith and the policeman laughed.“Do you know what ON THE HOUSE means?Look it up in the dictionary,It’s free meals for the first three days!” the policeman suggested . No machine

English translation Mr and Mrs Smith have just opened a small restaurant.In Order to attract customers, they put a notice in front of the restaurant, which said "means on the house for three days." A foreign student who didn’t know much English happened to pass by the restaurant on the second day.It "Well, here is a restaurant. I am going to have something to eat." he walked toward the restaurant when he saw the notice strange.They even eat dinners on the house!But how can I get up to the top of the house ” he said to himself. He looked around and found a ladder against a tree nearby.He was very glad.But as he reached the top he heard someone shouting at him.“ Hey ,what are you doing up there?” Mr Smith was looking at him angrily and beside him was a policeman. “Doesn’t your notice say ‘Meals on the House for Three Days’?Is it just a joke?” the foreign student answered . On hearing this,both Mr Smith and the policeman laughed.“Do you know what ON THE HOUSE means?Look it up in the dictionary,It’s free meals for the first three days!” the policeman suggested . No machine

Mr. and Mrs. Smith opened a new restaurant. In order to attract customers, they put up a notice in front of the hotel: free meals in three days! The next day, a foreign student passed by. He knew little English! It was lunchtime, and he felt very hungry! When he saw the hotel, he was going to eat. He walked towards the hotel, and suddenly found the

1. From a to B, go down the mountain first and then go on the level road. Someone goes down the mountain by bike at the speed of 12 kilometers per hour from a to B, and goes through the level road at the speed of 9 kilometers per hour. When he comes back, he goes through the level road at the speed of 8 kilometers per hour, and goes up the mountain at the speed of 4 kilometers per hour. It takes 1.5 hours to get the distance between a and B
2. Given y = ax & sup2; + BX + C. when x = - 1, y = 8, when x = 1, y = 0, when x = 2, y = - 1, find the value of y when x = - 2
3. The speed of Mr. Zhang's motorcycle is 45 km / h, and the speed of students' walking is 5 km / h. The distance between the school and the station is 15 km. If two students start from the school and want to arrive at the station within 50 minutes, they can ask Mr. Zhang to send them by motorcycle, but the back seat of the motorcycle can only seat one person. Students can't drive or use other means of transportation. They ask you to design a plan, It can make two students arrive at the station in the shortest time and find out the shortest time

1. Set the downhill time as X,
The time of leveling is 55 / 60-x
So the distance up the mountain is: 12x,
The distance of the flat ground is: (11 / 12-x) * 9
And then according to the speed and time series equation:
（11/12-X）*9/8+12X/4=1.5
X=1/4
The distance up the mountain is: 12 * 1 / 4 = 3km,
The distance of flat land is: (11 / 12-1 / 4) * 9 = 6 km,
3 + 6 = 9 km
two
A-B+C=8
A+B+C=0
4A+2B+C=-1
B=4
4A+8+C=-1
4A+C=-9
When x = - 2, y = 4a-2b + C = - 9-8 = - 17
three
Let a student ride the teacher's motorcycle with another student to the station, the teacher walked
The shortest time is 20 minutes. (15 / 45) × 60 = 20 minutes
If students don't know how to use motorcycles, they can do it in the following way
Mr. Zhang took a student on a motorcycle, walked with the rest of the student, and set out at the same time,
Then Mr. Zhang will send the first to the place x kilometers away from the station to return, and pick up another student on foot. Mr. Zhang will bring the students and the first students to the station at the same time
Then we can get the equation
Time for teacher to give first prize (15-x) / 45
The time for the first student to walk to the station is x / 5
The distance that the later students walk first is 5 * (15-x) / 45
It took [15-x-5 * (15-x) / 45] / (45 + 5) to meet again
The students who walked first walked 5 * {(15-x) / 45 + [15-x-5 * (15-x) / 45] / (45 + 5)}
The remaining distance is (45 * x / 5-x) / 2 + x = 5x
So the sum of the two is 15km
5*{(15-x)/45+[15-x-5*(15-x)/45]/（45+5）}+(45*x/5-x)/2+x=15
x=2.5km
The time for the teacher to send the first prize (15-x) / 45 = (15-2.5) / 45 = 16 minutes and 40 seconds
The time for the first student to walk to the station is x / 5 = 2.5 / 5 = 30 minutes
So it took 30 + 16.67 = 46 minutes and 40 seconds
reference material: http://zhidao.baidu.com/question/18492818.html?si=1
Hope to adopt and encourage~

How does a non right triangle know three sides to calculate area?

The most direct way is to use the cosine theorem to find out the cosine of an angle, find out its sine, and use the formula s = 1 / 2Ab sine C to find out its area!

Why does the third person singular predicate add s or es?

English is a kind of inflectional language. The so-called inflectional language is to make some changes at the end of the word on the basis of the original verb form to express different person, tense and tense. This is called "verb transposition". Many European languages, especially those originated from Latin, have very complex verb transposition. Every tense and every person verb are different

Inverse proposition and inverse theorem,
A counter example is given to show that the theorem "the median line of a triangle is equal to half of the third side" has no inverse theorem

In the triangle ABC, EF is the median line, e is the midpoint of AB, and F is the midpoint of AC. if EF = AC (this is possible), then the third side, half of BC, is equal to AC, so the inverse theorem does not hold

In the obtuse angle △ ABC, a, B and C are the opposite sides of angles a, B and C respectively. If a = 1 and B = 2, then the value range of the largest side C is ()
A. (1，5)B. (3，5)C. （2，3）D. (5，3)

∵ a = 1, B = 2, ∵ 2-1 ＜ C ＜ 2 + 1, i.e. 1 ＜ C ＜ 3, and △ ABC is an obtuse triangle, ∵ COSC ＜ 0, ∵ according to the cosine theorem, COSC = A2 + B2 − c22ab ＜ 0, i.e. A2 + b2-c2 ＜ 0, i.e. C2 ＞ 5, the solution is C ＞ 5, ∵ 5 ＜ C ＜ 3, then the value range of maximum edge C is (5,3)

The prototype, past tense and past participle of the verbs to be used in junior high school

Irregular verbs
Verb prototype (general present tense) verb past tense (general past tense) verb past participle (perfect tense, passive voice)
1 am,is was been
2 are were been
3 beat beat beaten
4 become became become
5 begin began begun
6 blow blew blown
7 break broke broken
8 bring brought brought
9 build built built
10 buy bought bought
11 can could not
12 catch caught caught
13 choose chose chosen
14 come came come
15 cost cost cost
16 cut cut cut
17 dig dug dug
18 do did done
19 draw drew drawn
20 drink drank drunk
21 drive drove driven
22 eat ate eaten
23 fall fell fallen
24 feel felt felt
25 find found found
26 fly flew flown
27 forget forgot forgotten
28 freeze froze frozen
29 get got got
30 give gave given
31 go went gone
Verb prototype verb past tense verb past participle
1 grow grew grown
2 hang hung,hanged hung;hanged
3 have,has had had
4 hear heard heard
5 hide hid hidden,hid
6 hit hit hit
7 hold held held
8 hurt hurt hurt
9 keep kept kept
10 know knew known
11 lay laid laid
12 learn learnt learnt,learned
13 leave left left
14 lend lent lent
15 let let let
16 lie lay lain
17 lose lost lost
18 make made made
19 May night
20 mean meant meant
21 meet met met
22 mistake mistook mistaken
23 put put put
24 read read read
25 ride rode ridden
26 ring rang rung
27 rise rose risen
28 run ran rung
29 say said said
30 see saw seen
31 sell sold sold
32 send sent sent
Verb prototype verb past tense verb past participle
1 set set set
2 shall should not
3 shine shone shone,shined
4 show showed shown
5 shut shut shut
6 sing sang sung
7 sink sank,sunk sunk,sunken
8 sit sat sat
9 sleep slept slept
10 smell smelt,smelled smelt,smelled
11 speak spoke spoken
12 spill spilt spilt
13 spit spat spat
14 spoil spoilt spoilt
15 stand stood stood
16 steal stole stolen
17 sweep swept swept
18 swim swam swum
19 take took taken
20 teach taught taught
21 tell told told
22 think thought thought
23 throw threw thrown
24 understand understood understood
25 wake waked,woke waked,woken
26 wear wore worn
27 will would not
28 win won won
29 write wrote written

Math problem, do me a favor~~~~~~~~~~~
The weight ratio of a and B barrels of oil is 4:3. After pouring 25 kg of oil from a barrel to B barrel, the weight ratio of a and B barrels of oil is 1:2. How many kg of oil were there originally?

Let a barrel be 4x kg and B barrel be 3x kg
(4X-25)/（3X+25）=1/2 X=15
So a barrel is 60kg, B barrel is 45kg

The impact of the development of genetic engineering technology on human beings and the main problems in its application

Gene engineering refers to consciously transferring useful target genes from one organism into another, so that the latter can obtain new genetic traits or products needed for expression, that is, the so-called transgenic technology. Transgenic technology has been widely used in industry and agriculture. With the rapid development of molecular biology and Biotechnology

there is a （c ）on our teacher's desk i
there is a （c ）on our teacher's desk in our classroom

Clock table