I am not sure ............ food tablets might supply enough energy for astronauts or not.

A. previous

B. following

C. before

D. last

A. They invited me a cup of tea.

B. They suggested drinking a cup of tea.

C. They advised her to drink a cup of tea.

D. They invited her a cup of tea.

A. My friend told me that he had just received a postcard from my aunt.

B. My friend told me that he had just received a postcard from his aunt.

C. My friend said me that he had just received a postcard from his aunt.

D. My friend told me that I had just received a postcard from my aunt.

A. She said that if the weather was fine, she would go on a picnic with her friends.

B. I said that if the weather was fine, she would go on a picnic with her friends.

C. She asked that if the weather was fine, she would go on a picnic with her friends.

D. She said if the weather was fine, I would go on a picnic with my friends.

A. not to go to bed

B. had better go to bed

C. to go to bed

D. go to bed

A. on - about

B. at - for

C. with - of

D. to – about

A. keeping silent

B. keep silent

C. kept silent

D. to keep silent