Do you like the book _______ is yellwo?
| A．whose cover | B．which cover | C．cover whose | D．cover which |
I once lived in a house _______ roof has fallen in.
| A．which | B．that | C．what | D．whose |
He has a friend _______ father is a doctor.
| A．who | B．whom | C．whose | D．which |
Could you tell me _______?
| A．where do you live | B．who you are waiting for |
| C．who were you waiting for | D．where you live in |
Is this the reason ______ at the meeting for his carelessness in his work?
| A．he explained | B．what he explained |
| C．how he explained | D．why he explained |