Câu hỏi: At times, this can be risky, and the keepers have been injured and one has been killed.

A. good

B. useful

C. healthy

D. secure

Câu 1: Use water sparingly and keep water clean.

A. dusty

B. dirty

C. wicked

D. halfway

Câu 2: Some couples see single women as a threat to their relationships.

A. married

B. lonely

C. divorced

D. alone

Câu 3: Fish only species that are not of concern, threatened or endangered.

A. educated

B. healed

C. defended

D. brought

Câu 4: We know not what is good until we have lost it.

A. find

B. count

C. guess

D. learn

Câu 5: Fish only species that are not of concern, threatened or endangered.

A. bettered

B. born

C. safeguarded

D. taught

Câu 6: He had never experienced such rudeness towards the president as it occurred at the annual meeting in May.

A. thought

B. hostility

C. care

D. politeness