There is no one in the classroom, he is still in the classroom dedicated to learning to modify the sick sentences

There is no one in the classroom, he is still in the classroom dedicated to learning to modify the sick sentences

There is no one in the classroom, he is still in the classroom dedicated to learning to modify the sick sentences, but I have really recovered, have learned map.baidu.com/tofeng . COM / yqoztm your past my last night

Through this reading activity, the students have increased their knowledge and broadened their horizons

This reading activity has increased students' knowledge and broadened their horizons
This reading activity has increased students' knowledge and broadened their horizons
Through cannot be used with

We can increase our knowledge and vision by reading extra-curricular books

Vision can't grow, it can be broadened
Should be: we read extracurricular books, can increase knowledge and broaden horizons

What season is China in when the sun is closest to the earth?

China is the winter solstice, because the earth's orbit around the sun is an ellipse, and its long diameter and short diameter are almost the same. The sun is at a focal point of the ellipse, but the focal point is not at the center of the ellipse. Therefore, the distance between the earth and the sun is sometimes closer, sometimes farther. At the beginning of January, the earth is closest to the sun, 147.1 million km, In fact, when the earth is at perihelion, the northern hemisphere is winter and the southern hemisphere is summer. At aphelion, the northern hemisphere is summer and the southern hemisphere is winter. At perihelion, the earth's revolution speed is faster than that at aphelion

A 750m long channel with isosceles trapezoid cross section is planned to be built in a forest farm. The cross section area is 1.6m2. The width of the upper entrance is 2m more than the depth of the channel, and the width of the bottom is 0.4m more than the depth of the channel
(1) What is the width of the upper opening and the bottom of the canal?
(2) If we plan to excavate 48 cubic meters of soil every day, how many days will it take to complete the excavation of this channel?
Please tell me the steps and ideas. I've worked out the formula, but it's not right. I feel it's wrong, so I'm going to ask for help now
Can you solve the second question? Why is it so listed,

Set: depth x top width x + 2 bottom x + 0.4
[（X+2）+ (X+0.4)]X/2=1.6
X = - 2 (round) x = 4 / 5
Top 14 / 5 bottom 6 / 5
1.6*750=1200
1200/48=25
So it's 25 days

There are two squares with a difference of 20 cm in circumference and 55 cm in area. What is the area of the small square? (solved by equation)

Let the side length of a large square be a centimeter
The side length of the small square is B cm
4a-4b=20
a^2-b^2=55
=(a+b)(a-b)=55
(a+b)*5=55
a+b=11
a-b=5
a+b=11
b=3
3 × 3 = 9 (square centimeter)
The area of a small square is 9 square centimeters

How to calculate the law of multiplicative distribution?
 

25×44
＝25×（40+4）
＝25×40+25×4
＝1000+100
＝1100

4cos²α-2(1+√3)cosα+√3=0

Decomposition factor: (2cos α - 1) × (2cos α - √ 3) = 0;
The results show that cos α = 1 / 2 or cos α = √ 3 / 2
It is deduced that: α = ± π / 3 + 2K π or α = ± π / 6 + 2K π

On a rectangular grassland, there is a curved asphalt path (the length of any line parallel to ab cut by the path is 1m)
Can you imagine the area of grassland in the blank?

∵ the rectangular area is (AB) m, and the width of the path is 1m. If the path is removed, the two pieces of grassland can be put together into a new grassland. The width is removed by 1m of the original path, that is, (A-1) m, and the length is unchanged, or BM,
The grassland area is (A-1) B = AB-1 × B = ab-b
Give a good comment, it's my support!

What is the ratio of 21 / 9 to 7 / 12

=7/3:7/12
Divide by 7
=1/3:1/12
Multiply by 12
=4:1