Every few years, the coal workers                 their lungs X-rayed to ensure their health.
#102390
A
are having
B
have
C
have had
D
had had
推荐题目
A: Hi , Randall,Come on in .B: Uh, yeah, I     by to see if you       for a roommate to share your house.
#103994
A
stopped; were still looking
B
will stop ;are still looking
C
have stopped ; were still looking
D
stop ; will have looked
He looked as though he _________ a ghost(鬼).
#103810
A
saw
B
has seen
C
have seen
D
had seen