They tried several times to       the problem, and in the end they succeeded.
#61763
A
give up
B
work out
C
look through
D
think of
推荐题目
— When  _________ the car _________ ?—   In 1885. 
#56782
A
did;invent
B
was;invented
C
does;invent
D
is;invented
It is foggy(多雾的) today. The plane can't       .
#54893
A
land
B
landed
C
take off
D
taking off
The small boys decided ________ to each other.
#58266
A
not talk
B
not talking
C
not to talk
D
talk