I am so tired,for I ________ English for 2 hours.
#99761
A
is studying 
B
have been studying
C
was studying 
D
had been studying
推荐题目
 -I haven't heard from Henry for a long time. -What do you think ________ to him? 
#104036
A
happening
B
to happen
C
has happened
D
had happened
The meeting        for two hours,but they still       any agreement.
#102274
A
has been going on;haven’t reached
B
has been going on; haven’t been reached
C
was going on; haven’t reached
D
was going on; haven’t been reached