David doesn’t give up _______ he has failed in the experiment four times.
#57463
A
if
B
while
C
though
D
since
推荐题目
---Where was your sister at this time yesterday evening ? ---She was writing an e-mail ______ I was watching TV at home.
#57132
A
after
B
as soon as
C
while
D
until
Cycling isn’t _________ climbing, but both of them are interesting.
#55547
A
as exciting as
B
as more exciting as
C
as excited as
D
as more excited as
The boy ___________ go to bed _________ his mother came back.
#58156
A
won’t ; until
B
didn’t ; until
C
will ; until
D
won’t ; before