．If I _________too late last night, I could not have fallen asleep in class.
| A．didn’t stay up | B．hadn’t stayed up |
| C．don’t stay up | D．haven’t stayed up |
The number of the audience，________ we had expected，was well over one thousand.
| A．whom | B．who | C．which | D．as |
A lot of language learning，________ has been discovered，is happening in the first year of life，so parents should talk much to their children during that period.(2012·安徽，29)
| A．as | B．it | C．which | D．this |
The air quality in the city，________ is shown in the report，has improved over the past two months.(2012·福建，23)
| A．that | B．it | C．as | D．what |
—What do you think of teaching，Bob?
—I find it fun and challenging.It is a job ________ you are doing something serious but interesting.
| A．where | B．which | C．when | D．that |
It's helpful to put children in a situation ________ they can see themselves differently.
| A．that | B．when | C．which | D．where |