So far, the moon ________ by man already.  
#38542
A
is visited
B
will be visited
C
has been visited
D
was visited
推荐题目
Ssh, please be quiet. The baby _______ .
#40226
A
sleep
B
sleeps
C
is sleepping
D
is sleeping
A young man ___ John _____ school recently.
#42489
A
calling; has left
B
called; will leave
C
calling; is leaving
D
called; has left