_____ that air conditioners cause so much pollution, I would never have bought one.
| A．Had I known | B．I had known | C．Were I to know | D．Did I know |
Human facial expressions differ from those of animals in the degree __________ they can be controlled on purpose.
| A．with which | B．to which |
| C．of which | D．for which |
Chan’s restaurant on Baker Street, __________ used to be poorly run, is now a successful business.
| A．that | B．which |
| C．who | D．where |
Those successful deaf dancers think that dancing is an activity __________ sight matters more than hearing.
| A．when | B．whose |
| C．which | D．where |
It is reported that two schools, __________ are being built in my hometown, will open next year.
| A．they both | B．which both |
| C．both of them | D．both of which |
Today, we’ll discuss a number of cases __________ beginners of English fail to use the language properly.
| A．which | B．as |
| C．why | D．where |