1. She isn't old enough to ride a motorbike.

- S +tobe + too + adj + to_V + O

= S + tobe + not + adj ( trái nghĩa) + enough + to_V + O

-> ai đó không đủ ... để làm gì.

2. Because of a stomach ache, he didn't go camping with us yesterday

- Because + A clause, a clause 

= Because of + N/V_ing, S + V + O

-> bởi vì

3. She has studied English for three years.

- S + started / began + V_ing + O + time + ago

= S + has/have + V3/ed + O + for + time.

-> Ai đó đã bắt đầu làm gì khi nào.

4. It takes her three hours to prepare dinner

- S + spend(s) + time /money + V_ing + O

= It + takes + time/money + to_V + O

-> ai đó dành thời gian/ tiền làm gì

5. She said that it was very quiet there

- Câu tường thuật dạng câu kể:
S + said/told + (that) + S + V(lùi thì)

- lùi thì: HTĐ -> QKĐ

- here -> there