No one can walk the wire in the air without a bit of fear unless ______ very young. 
#95230
A
having trained
B
trained
C
to be trained
D
being trained
推荐题目
Once _____ , the machine will keep running.
#94334
A
start
B
started
C
to start
D
starting
Having finished her project ,she was invited by the school______ to the new students.
#89788
A
speaking
B
having spoken
C
to speak
D
to have spoken
______ the project in time, the staff are working at weekends.
#90646
A
Competing
B
Having completed
C
Completed
D
To complete