____ several times, the young scientist still kept on doing his experiments.
#92897
A
Having failed
B
Having been failed
C
Failed
D
To fail
推荐题目
Today everyone arrived earlier than _______.
#97679
A
expecting
B
having expecting
C
to expect
D
expected
The teacher looked at the student with a smile as if ______ him to answer the question.
#96507
A
expected
B
to expect
C
expecting
D
expect
The boy finally was beginning ___ his mistakes.
#97750
A
that he saw
B
for him to see
C
seeing
D
to see
Air pollution, together with littering, ____ many problems in our large industrial cities today.
#96011
A
causes
B
cause
C
caused
D
causing
I remembered _____ the door before I left the office, but forgot to turn off the lights.
#93451
A
locking
B
to lock
C
having locked
D
to have locked