1. Your father has used to smoke five years ago.

2.His performance made a deep impression on us. 

3.The machine which the man used to cut the grass is very modern.

Ta có công thức: 

a x a x a = V (a là cạnh HLP) 

(a x 4) x (a x 4) x (a x 4) = V x 64

=> Thể tích tăng thêm 64 lần.

Số thứ nhất và số thứ hai đều gấp lên hai lần thì tổng hai số là: 43 x 2 = 86

Hai lần số thứ nhất là: 122 - 86 = 36 

Số thứ nhất là: 36 : 2 = 18

Số thứ hai là: 43 - 18 = 25

 Đ/S: Số thứ 1: 18

         Số thứ 2; 25 

Children participate in learning activities at school for a while and parents can clearly see how children are engaged in activities. It's not uncommon for parents to receive the first report card saying, "I'm not paying attention and I'm easily distracted." Just because a child has trouble concentrating doesn't mean he or she doesn't work hard or isn't smart. It also doesn't mean that the child doesn't care about anything, even though we see him as it does. Your child may want to focus on something, but can't. Problems in children can appear in many ways and these problems can change over time. There are some behaviors that parents may notice in their children such as:

+ Unable to sit still.

+ Easily distracted.

+ Difficulty in participating in school activities.

+ Difficulty completing schoolwork

15.Flying suitcase will be placed here.

16.Dynamite fishing is not permitted here.

Tôi không vì học nhiều, tôi nên thấy mình biết còn quá ít.