We _______ on it for several hours but we have not yet reached any conclusion.
#104695
A
work
B
areworking
C
havebeenworking
D
havebeenworked
推荐题目
The police           the murderer everywhere when he suddenly appeared in a theatre.
#100698
A
is searching for
B
were searching for
C
are searching for
D
were searching
Look at the timetable. Hurry up! Flight 4026      off at 18:20.
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A
takes
B
is taking
C
will be taken
D
has taken