-This problem is very difficult.       -I know,but Jack has           working it out. 
#38799
A
succeed in
B
succeeds in
C
succeeding in
D
succeeded in
推荐题目
I won’t go to the concert because I _______ my ticket.
#37539
A
lost
B
don’t lose
C
have lost
D
will lose
I met a good friend of mine while I     on the street.
#42098
A
walks
B
walk
C
was walking
D
am walking
—I wonder if you ____ a picnic tomorrow.—Yes. But if it ___, we’ll visit the museum instead.
#38517
A
have; rains
B
will have; rains
C
have; will rain
D
will have; will rain
---- Who ______ the room?  ----My brother______. 
#40083
A
clean , is
B
clean does
C
cleans, is
D
cleans, does
---     you having supper at this time yesterday?---No, I was     .
#40087
A
Are; having a rest
B
Were; read a book
C
Are; watching TV
D
Were; singing