Do you know what ___ while you were away from home?
| A．had happened | B．was happened | C．has happened | D．happened |
I was about to go to bed _____ one of my old classmates made a call to me.
| A．that | B．as | C．while | D．when |
Only those ____knew well could be let in.
| A．who | B．which | C．what | D．he |
The criminal, as well as some ______ people, was arrested by the police yesterday.
| A．relevant | B．skilled | C．evil | D．lucky |
____ with the size of the whole earth, the highest mountain doesn’t seem high at all.
| A．To compare | B．while comparing | C．It comparing | D．when compared |
I ______ my university professor in the supermarket near my house, which was out of my expectation.
| A．came out | B．came across | C．came about | D．came along |