问题
I was reading attentively in my own room _____ suddenly he knocked at the door[ ]
A: when
B: while
C: then
D: as
B: while
C: then
D: as
正确答案是：
同类题型
incipal walked onto the platform and seatedhimself in a chair, ____ for answering questions.
When one end of the chopstick is in the water, it looks as if it____________.[ ]
The plane finally landed and not a single passenger ______.
The girl sat in the corner quietlynone of us noticed she wasthere.