I don’t smoke now, but I _______ for more than twenty years. 
#100053
A
smoked
B
was smoking
C
have smoked
D
had smoked
推荐题目
When a pencil is partly in a glass of water, it looks as if it _______. 
#104039
A
breaks
B
has broken
C
were broken
D
had been broken
Stop! You can never touch this machine when it ________, it is very dangerous. 
#102729
A
has been operated
B
will be operated
C
is operated
D
is being operated
----- How long ________ in Guilin? ----- For two weeks. I’m going to some places of interest there.
#101791
A
did you stay
B
do you stay
C
are you staying
D
have you stayed