Câu hỏi: 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 1: It is very difficult for her to prevent him for smoking in her house.

A. very

B. for 

C. prevent 

D. for smoking

Câu 2: Each of the members of the group were made to write a report every week.

A. were

B. members

C. to write

D. week

Câu 3: Some of his favourite subjects at school are Maths, English and Geographical.

A. some

B. subjects

C. are

D. Geographical

Câu 4: Ancient people made a clay pottery because they needed it for their survival.

A. a clay pottery

B. because

C. it

D. their survival

Câu 5: The number of students attending universities to study economics have increased steadily in the last few years.

A. of students

B. attending

C. economics

D. have

Câu 6: My elder sisters, both of them were doctors, said they were too busy to pick me up.

A. elder

B. both of them

C. too busy 

D. to pick