`7` earlier

`->` So sánh hơn - adv ngắn : S1 + V(chia theo thì) + adv-er + than + S2

`->` Dấu hiệu : có "than"

`8` the best

`->` So sánh nhất - adj ngắn: S + tobe + the + adj-est 

                               adj dài : S + tobe + the +  most adj 

`9` more easily

`->` So sánh hơn - adv dài : S1 + V(chia theo thì) + more adv + than + S2

`->` Dấu hiệu - than

7. The Great Wall was built........(early) than the White House. 

=> The Great Wall was built earlier than the White House. 

8. Mary is ......... (good) student in my class.

=> Mary is the best student in my class.

9. This task can be completed ........ (easily) than that one.

=> This task can be completed more easily than that one.