11.  When do we use the one and when do we use the orther ?

12.  When do we use the one and when do we use the other?

13.  How to use them?

14.  I must use it to study well .

15.  and prepare their lessons .Many people know the time is inportant , but they don't know how to use the time to do some useful thing .

16.  that time we used to be happy, but then everything was changed .

17.  The teacher told us there about 1500, she also said that English is one of the most important languages because so many people use it, not only in England and America, but in other contries of world, so study English is very important for us , if we study English well, it will be very useful for us .

18.  he is using the language, thinking in it and talking in it all the time.

19.  Only when he can use the new language without thinking of his own language , we can say that he can learn a foreign language."

20.  The first lesson was English, the teacher taught us some sentences which used usually .