Sally has been swimming ______ four hours.   
#50710
A
for about
B
since
C
about
D
/
推荐题目
St Peter’s Church is _____ the museum.
#48072
A
over
B
opposite
C
across
D
in
Thank you______your help.
#46599
A
for
B
of
C
with
D
on
His mother is friendly____ us.
#48964
A
of
B
to
C
on
D
at