`11.` C. The coffee was not strong enough to keep us awake.
- Cấu trúc enough to: S + be (not) + adj+enough + (for sb) + to V
`12.` Despite his broken legs, he was able to get out of the car before it exploded.
- Despite/In spite of + N/N phrase/V-ing, S + V + …
`13.` D. That exercise is not as easy as this one.
- So sánh ngang bằng: S + be (not) + as + adj + as + N/pronoun.
`14.` D. The black dress is more expensive than the green dress.
- expensive >< cheap
`15.` B. My apartment is not as big as your apartment.
- Cấu trúc như câu 13
`16.` D. Kien drives more carelessly than Tam.
- S1 + V + more + adv + than + S2
`17.` D. Tennis is not as dangerous as snowboarding.
- So sánh ngang bằng: S + be (not) + as + adj + as + N/pronoun.
`18.` B. My house isn’t as modern as yours.
- Cấu trúc như câu 13