I had to stand up and give a short speech_________the guest lecturer who cancelled at the last minute.

A. mistakes

C. changes

A. simple – simplicity

B. simplicity – simple

C. simplified – simplicity

A. After the USA put the first human on the moon, Russia had already sent the first human into space.

B. Before the USA put the first human on the moon, Russia had already sent the first human into space.

D. The USA put the first human on the moon before Russia had already sent the first human into space.

A. The place has a microgravity environment where astronauts live and conduct research.

B. The place which astronauts live and conduct research has a microgravity environment.

C. The place where astronauts live and conduct research has a microgravity environment here.

D. The place where astronauts live and conduct research has a microgravity environment.

D. take

A. Ø – the

B. the – the

C. the – Ø

A. Quang, whom lives next door plays the piano very well.

B. Quang, whose lives next door plays the piano very well.

C. Quang, that lives next door, plays the piano very well.

D. Quang, who lives next door, plays the piano very well.