II: 1. If i were him, I would choose English
2. We are used to going fishing on the weekend (be used to V-ing: quen làm gì, thói quen)
3. This room should be cleaned everyday
4. We have known each other since we were small
5. She is looking forward to seeing her friends again

1. If I were him, I would choose English.

⇒ If 2 : If + S1 + V2/ed, S2 + would + Vinf

2. We used to go swimming at weekend.

⇒ used to + Vinf: đã từng

3. This room should be cleaned everyday.

⇒ Câu bị động với should: S + should + be + Vpp

4. We have known each other since we are small.

⇒ hiện tại hoàn thành + since + quá khứ đơn

5. She is looking forward to seeing her friends again.

⇒ look + forward + to Ving