Câu hỏi: Although most species of small birds gather in groups at feeders provided by bird-watchers, the bright red cardinals usually appears alone or with its mate.

A. at

B. cardinals

C. or

D. its

Câu 1: Proteins are made up of folded irregularly chains, the links of which are amino acids.

A. made up of

B. folded irregularly

C. the links

D. which

Câu 2: If you take the train, it would be much more convenient.

A. if

B. the train

C. would be

D. much

Câu 3: My teacher is very strict and he always makes us to finish all the exercises before leaving school.

A. is

B. strict

C. to finish

D. leaving school

Câu 4: My sister told me that she had met my teacher at the supermarket yesterday.

A. My sister told

B. had met

C. at the supermarket 

D. yesterday

Câu 5: A smile can be observed, described, and reliably identify, it can also be elicited and manipulated under experimental conditions.

A. identify

B. experimental

C. can also

D. A smile

Câu 6: If they took their language lesson seriously, they would be able to communicate with the locals now.

A. took

B. seriously

C.  would be

D. with the locals