Time waits for no man． But some people won't realize the importance of time______it's gone．（ ）
A．asB．sinceC．whenD．until
My son lives a little far from his office， so he always goes go work bus．（ ）
| A． |
on |
B． |
by |
C． |
with |
D． |
in |
I have difficulty working out the problem by myself．Could you help me？
_____________．（ ）
| A． |
It's my pleasure |
| B． |
With pleasure |
| C． |
No，l couldn't |
The child is crying．Please do something to make him_____．（ ）
| A． |
stop to cry |
| B． |
stop crying |
| C． |
to stop crying |
I don't know when he back．Please tell me when he back．（ ）
| A． |
comes，comes |
| B． |
comes，will come |
| C． |
will come，comes |
Two months ____ a long time．We can visit our grandparents during the vacation．（ ）
| A． |
am |
B． |
is |
C． |
are |