They were busy ________ an experiment when I came.
#92445
A
doing
B
to be doing
C
with doing
D
to do
推荐题目
His first book ________ next month is based on a true story.
#95077
A
published
B
to publish
C
to be published
D
being published
Life is like riding a bicycle. ________ your balance, you must keep moving.
#88762
A
Keeping
B
To keep
C
Keep
D
Having kept
——Can the project be finished as planned?—— Sure, _________ it completed in time, we’ll work two more hours a day.
#90817
A
having got
B
to get
C
getting
D
get
Tom has been out of work for two years, so he has difficulty______.
#97290
A
earning living
B
earning his living
C
to earn livings
D
to earn his living