Although the causes of cancer ____we do not yet have any practical way to prevent it.
#105341
A
are being uncovered
B
have been uncovering
C
are uncovering
D
have uncovered
推荐题目
What shall we use for power when all the oil in the world has ?
#105323
A
given out
B
put out
C
held up
D
used up
8.Customers are asked to make sure that they ____ the right change before leaving the shop.
#105342
A
will give
B
have been given
C
have given
D
will be given
— Who is ____ the TV show? She seems to be talented. — Mary Green, who used to be a great actress.
#105321
A
opening
B
hosting
C
playing
D
seeing
It's really time I went home but I'm enjoying myself, so I ________ here a bit longer.
#105318
A
am staying
B
have stayed
C
stayed
D
stay
—I'm not finished with my dinner yet.—But our friends ________ for us.(2010·北京)
#105317
A
will wait
B
wait
C
have waited
D
are waiting