The students _______ their homework carefully when the teacher walked into the classroom quietly.
#36148
A
do
B
did
C
are doing
D
were doing
推荐题目
-Where _______ the 2008 Olympic Games _______?.-You don’t know? Beijing!
#38475
A
will; hold
B
has; been held
C
was; held
D
will; held
If it         tomorrow, I’ll go out for a walk with you. 
#39555
A
doesn’t rain
B
won’t rain
C
hasn’t rained
D
isn’t raining
Robert is away. He _______ America since last week.
#36502
A
has been to
B
has joined a club in
C
has studied in
D
has become a manager in