We have only one earth. We should ____ and take actions to protect it.
A. stop to pollute B. stop polluting
C. to stop to pollute D. to stop polluting
Simon wanted to study abroad， but his mother asked him to ______.
A. think of it B. think it of
C. think it over D. think over it
It is dangerous to make the little boy ____ at home by himself.
A. stay B. staying C. to stay D. stayed
When did you ______ Hongkong?
A. returned to B. go back
C. return back to D. return to
My grandparents lived ____ in the country. Sometimes they felt a bit ____.
A. lonely， lonely B. alone， alone
C. alone， lonely D. lonely， alone
Most students _______ living in the school.
A. used to B. is used to
C. are used to D. are use to
