A.mosquito
B.envelope
C.delighted
D.recycle

It's difficult to avoid traffic jams during rush hours.
A.There are always traffic jams on streets.
B.It's difficult to travel during rush hours.
C.To avoid traffic jams during rush hours in difficult.
D.Traffic jams are difficult to avoid.

The boy is very young. He can't understand the story.
A.The boy is young and he can't understand the story.
B.The story is difficult for the boy to understand.
C.The boy is too young to understand the story.
D.The boy is young, he doesn't like the story.

A.count
B.content
C.celebrate
D.call

A.replace
B.purchase
C.surface
D.palace

A.care
B.are
C.stare
D.dare

A.complain
B.machine
C.music
D.instead

A.biology
B.redundancy
C.interviewer
D.comparative

A.doctor
B.modern
C.comer
D.Chinese

Mary_______ write to me last year.
A.uses to
B.used to
C.is used to
D.was used to