The Russian rocket designer has died. For many years, he ______ as an important assistant to the father of Soviet space program.
#101576
A
serves
B
was serving
C
served
D
has served
推荐题目
--I’m going to the States?--How long ________ you________ in the States?
#101653
A
are; stayed
B
are; staying
C
have; stayed
D
did; stay
He would have gone to visit Linda yesterday, however , he _____on by Linda instead.
#101972
A
was called
B
called
C
would be called
D
has been called
The central heating system of this office building is down and several workers ______ it right now.
#99933
A
had repaired
B
have repaired
C
repaired
D
are repairing
She ___ volleyball regularly for many years when she was young．
#102443
A
was playing
B
played
C
has played
D
had played
The town’s drinking-water _____ with prim chemicals at present.
#104183
A
contaminates
B
is contaminated
C
is being contaminated
D
has been contaminated