1. It took me three months to accomplish this task (It + take + s.one + time/money + to do s.th)
2. The toy made her happy (make s.one + adj: làm ai như thế nào)
3. I have studied English for 3 years (S + started/began + to V/V_ing + ..... = S + have/has + Vp.p + ...; for + khoảng thời gian: HTHT = khoảng thời gian + ago: QKĐ)
4. I haven’t seen him since I was a student (S + last + V+ed/2 + ..... = S + have/has + not + Vp.p + ...; since + mốc thời gian: HTHT = when/in + mốc thời gian: QKĐ)
5. When did you have it?