We all agree that _______ good knowledge of physics is a must in explaining such _______ natural phenomena.
| A．a; / | B．a; a | C．/; a | D．/; / |
In the dark street, there wasn’t a single person _____ she could turn for help.
| A．that | B．who | C．from whom | D．to whom |
The weather turned out to be very good, ____ was more than we could expect.
| A．what | B．which | C．that | D．it |
After living in Pairs for fifty years he returned to the small town ____ he grew up as a child.
| A．which | B．where | C．that | D．when |
Carol said the work would be done by October, ＿＿＿＿＿personally I doubt very much.
| A．it | B．that | C．when | D．which |
He was hiding behind the door _________ he could see what was happening.
A. whichB. from whereC from which D. where