On the use of punctuation marks C. If students fail to meet the standards in examinations, they can not be given a chance to fail. It is necessary to study the reasons why students fail to meet the standards. Are the teachers' own guidance not perfect, or are the students with defects in their qualifications and omissions in their studies? We should try our best to remedy or urge them The first question mark should be replaced by a comma. The second question mark should be deleted because the dash acts as a bracket. I don't understand it, I think it's OK to change the first question mark into a comma. Please help me analyze it, but don't copy or paste a lot of it thank you!

The first question mark is changed into a comma, because this sentence is not a question sentence, it does not mean to ask, it is just to explain a fact. There should not be any punctuation mark at the second question mark, because the -- in this place plays the role of explanation, which is equivalent to (), and there should not be any punctuation before these two kinds of punctuations

How to use punctuation on keyboard

There are many punctuation marks on the keyboard. They are all marked on the keyboard. The owner can directly press the subscript key and it will come out. The general punctuation key will have two symbols. One click will only bring out one symbol, such as the semicolon and colon beside the L key. If you press this key, it will only bring out semicolon. If you want to type a colon, Then you have to hold down the shift key in the lower left corner of the keyboard, and then press the semicolon colon key. At this time, you will find that the colon comes out. Other punctuation keys are the same. The symbol below each key is pressed directly, and the symbol in the row above the key needs to be completed through the combination of shift. I wish you success

1.5 times of a number is 17 less than two-thirds of 27. What's the number? (solve the equation)

This number is X
1.5x=2/3*27-17
1.5x=18-17
x=2/3

Given that the eccentricity of the ellipse C (0,1) with focus on X axis is √ 3 / 2, and M is the right vertex of ellipse C, the standard equation of ellipse C is obtained

Let the equation be: x ^ 2 / A ^ 2 + y ^ 2 / b ^ 2 = 1, (a > b > 0), according to the meaning of the question: B = 1, C / a = √ 3 / 2, because B ^ 2 = a ^ 2-C ^ 2, so: 1 = a ^ 2-C ^ 2, that is: A ^ 2 = 1 + C ^ 2, from C / a = √ 3 / 2: C ^ 2 = 3A ^ 2 / 4, so: A ^ 2 = 1 + 3A ^ 2 / 4, the solution is: A ^ 2 = 4, so: the equation is: x ^ 2 / 4 + y ^ 2 = 1

The first five terms of the sequence are the following numbers. Write a general formula of the sequence: (1) 1, 1 / 3, 1 / 5, 81 / 7, 1 / 9 (2)
The first five terms of a sequence are the following numbers. Write a general term formula for each sequence:
（1）1 ,1/3 ,1/5,81/7 ,1/9
（2）-1/2×1 ,1/2×2 ,-1/2×3 ,1/2×4 ,-1/2×5
（3）1 ,√2/2,1/2 ,√2/4 ,1/4

（1）a(n)=1/(2n-1)
（2）a(n)=[(-1)^n]/(2n)
（3）a(n)=(√2/2)^(n-1)

176 degrees 52 minutes / 3

176°52′÷3=58°57′
176°52′÷3=(174°+2°52′)÷3
=(174°+172′)÷3=58°57′

What fraction is 2.65

What fraction is 2.65
2 and 13 / 20
I am a teacher

Let the common ratio Q of the equal ratio sequence {a}

S4=a1(1-q4)/(1-q),S2=a1(1-q2)/(1-q),
If S4 = 5s2, then A1 (1-q4) / (1-Q) = 5A1 (1-q2) / (1-Q),
That is, q = ± 2,
It's more common than Q

Solution equation: 5 / 6 + x = 19 / 24

x=19/24-5/6=-1/24

Two thirds of a meter can represent not only the fraction of one meter, but also the fraction of two meters?

Two thirds of a meter means two thirds of a meter and one third of a meter