What were you doing ______ I knocked at the door？
I was sleeping．（ ）
A．unlessB．onceC．whenD．while
Miss Chen， my dear English teacher， often encourages me ______the challenges in my study．（ ）
| A． |
face |
B． |
faces |
C． |
facing |
D． |
to face |
These machines_____in their factory by themselves last year．（ ）
| A． |
make |
B． |
made |
C． |
are made |
D． |
were made |
Listen! The birds ______ in the trees outside our school．（ ）
| A． |
sing |
B． |
are singing |
| C． |
sang |
D． |
were singing |
Lisa made so many mistakes in her homework， because she didn't do it ______enough．（ ）
| A． |
carefully |
B． |
busily |
C． |
quickly |
D． |
warmly |
We have wider____in our village， so we can go out more easily now．（ ）
| A． |
houses |
B． |
roads |
C． |
schools |
D． |
hospitals |