With the help of high technology, more and more new substances ___in the past few years.
#101737
A
discovered
B
have discovered
C
had been discovered
D
have been discovered
推荐题目
—What do you think of the film Avatar?—It________be better.I even want to see it twice.
#101054
A
couldn’t
B
won’t
C
shouldn’t   
D
mightn’t
I'm sorry. I _____________ you__________ to me.
#104802
A
don't know; are speaking
B
don't know ;were speaking
C
didn't know; were speaking
D
didn't know; are speaking
— Have you graduated from collage?— Yes, ________.
#101444
A
I studied French for two years.
B
I have been studying French.
C
I have studied French for two years.
D
I had studied French for two years.