So far, the moon ________ by man already.  
#38542
A
is visited
B
will be visited
C
has been visited
D
was visited
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My parents often______ me some gifts on my birthday.
#39504
A
buy
B
will buy
C
buys
D
has bought
 After Steven sent some e-mails ,he______ surfing the Internet.
#36785
A
starts
B
has started
C
will start
D
started