Have you realized the difficulty we have ____ the problem?
#96909
A
worked out
B
to work out
C
work out
D
working out
推荐题目
 ______ herself with other girls, she feels she is quite lucky.
#98243
A
Comparing
B
Compared
C
To compare
D
Being compared
Tom, look at your shirt! It requires ________. 
#90771
A
washing
B
washed
C
to wash
D
being washed