You _______ go through the security check (安检) before getting on the train.
A. can B. must C. may D. might
This house is one of ________ buildings in the town．We must take actions to protect it．
A. old B. older C. oldest D. the oldest
The manager sounded _________ on the phone．He offered to show us around the company．
A. softly B. friendly C. hardly D. carefully
—Look! So many colorful bicycles in two lines over there.
—They’re for public. This kind of green smart traffic is ______ in big cities now.
A. everything B. everyone C. everyday D. everywhere
When Jack arrived _____the airport，he found it hard to look for a place to park his car．
A. in B. at C. on D. to
On no-car day, ______ students ______ teachers are allowed to drive to school.
A. either; or B. not only; but also C. neither; nor D. both; and
