Rewrite sentences 1 She was very tired,so she went to bed She went 2 I haven't eaten this kind of food before this is the first time 3 To use solar energy for a number of days is possible It is 4 If we use solar energy,we can save natural resources By 5 It's not necessary for you to finish it by Saturday You

`1.` She went to bed because she was very tired

`-` Because + Clause(nguyên nhân), Clause( kết quả) : bởi vì

`=` Clause (nguyên nhân) + ,So + Clause( kết quả): .... vì vậy ....

`2.` This is the first time I have eaten this kind of food.

`-` This is the first/second/.... time + S + Clause(HTHT) : Đây là lần đầu/hai/....

`+` Hiện tại hoàn thành : `(+)` S + have/ has + PII 

`**` She, he, it và N số ít - has

`**` I, you, we, they và N số nhiều - have

`3.` It's possible to use solar energy for a number of days

- It's adj (N) (for smb) to do smt

`4.` By using solar energy, we can save natural resources

`-` By doing smt : Bằng việc ........

`-` can do smt : Có thể làm gì

`5.` You don't have to finish it by Saturday

- (not) have to V : (không) phải làm gì 

- Hiện tại đơn : (-) S + don't/doesn't +V

`+` She, he, it và N số ít - does

`+` I, you, we, they và N số nhiều - do