1 Students have to put their mobiles into schoolbags during lessons.

`-` be compulsory + to V `=` have to + Vinf : phải làm gì.

2 We don't speak English as fluently as the students do.

`-` SS bằng: S1 + V + as + adj/adv/N + as + S2.

3 John's sister sings better than he does.

`-` SS hơn trạng từ ngắn: S1 + V + adv + er + than + S2.

4 You speak too fast for me to catch up with your words.

`-` S + V + too + adj/adv/N + for O + to V + O: Ai đó làm gì quá như thế nào cho ai làm gì.

5 Mary doesn't have enough money to buy that Martin bicycle.

`-` S + V + enough + N + to V + O: Ai đó làm gì đủ để làm gì.

1. Students have to put their mobiles into school bags during lessons.

have to + V1: phải làm gì 

2. We don't speak English as fluently as the students.

S + V +as + ADV + as+ O: so sánh bằng

3. John's sister sings better than him.
S  +V + better than + O : so sánh hơn 

4. You speak too fast for me to catch up with your words.

S + V + too + ADV + (for O) + to V; quá... đến nỗi không

5. Mary doesn't have enough money to buy that Martin bicycle.

S + (not) + V + enough + N + (for O) + to V: (không) đủ... để làm gì

`color{orange}{~LeAiFuRuiHuiBao~}`