=>
1. is not studying/is helping/clean ( now -> thì HTTD/ help sb V)
2. didn't work ( vế sau would -> câu đk loại 2)
3. was ( câu tường thuật They asked her -> lùi thì)
4. didn't have to/has had ( since QKĐ, HTHT)
5. met ( yesterday -> QKĐ)
6. doesn't watch/watches ( often -> thì HTĐ)
7. not to buy ( advise sb (not) to V)
8. organizing ( suggest Ving)
9. gets/goes ( usually -> HTĐ)
10. has/will come (câu đk loại 1 If S Vs/es, S will V)
11. was cooking ( when QKĐ, QKTD)
12. lived ( said -> câu tường thuật)