Câu hỏi: The famous racehorse Secretariat had to be destroyed because of a painful, incurable hoof disease.

A. disabling

B. vexatious

C. dangerous

D. irreparable

Câu 1: Scientists warn of the impending extinction of many species of plants and animals.

A. irrefutable

B. imminent

C. formidable

D. absolute

Câu 2: He was fired because of his misconduct at the office party.

A. mistake

B. impropriety

C. condition

D. singing

Câu 3: The 1908 Siberian meteorite explosion brought about considerable depletion of the northern hemisphere's ozone layer.

A. was caused by

B. resulted in

C. brought back

D. was initiated by

Câu 4: The museum dismissed the curator after some of the oldest paintings were damaged.

A. artist

B. cleaner

C. guard

D. director

Câu 5: We watched as the plane disappeared behind the clouds.

A. melted

B. escaped

C. vanished 

D. perished

Câu 6: In the United States, a party can nominate a single candidate for office.

A. refuse

B. keep

C. change

D. appoint