Let's chat online．
______（ ）
| A． |
Not at all |
B． |
Thank you |
C． |
Good idea |
D． |
Good luck |
This math problem isn't so difficult that I can work it out ________．（ ）
| A． |
easily |
B． |
usefully |
C． |
loudly |
D． |
quietly |
John is _______ American student．（ ）
| A． |
a |
B． |
an |
C． |
the |
D． |
/ |
Please ____ the dog for me while I'm away．（ ）
| A． |
look |
B． |
look after |
C． |
look up |
D． |
look out |
Nick didn't have dinner ________ be finished doing homework．（ ）
| A． |
if |
B． |
when |
C． |
until |
D． |
after |
_____ has the girl waited for the bus over there？
For half an hour．（ ）
| A． |
How often |
B． |
How many |
C． |
How long |
D． |
How soon |