It took several hundred years ______ paper-making spread to western countries.
#33423
A
when
B
before
C
after
D
since
推荐题目
 __________I see him, he looks sad.
#31022
A
Every now and then
B
Every now and again
C
Every so often
D
Every time
_______ she was invited to the ball made her very happy.
#31131
A
Whether
B
That
C
Because
D
What
The little boy was allowed to go swimming _______ he kept near the other boys. 
#31481
A
provided that
B
in case
C
now that
D
by the time