_____ these experiments were successfully completed would we think of
going into humans.
| A．If only | B．So that | C．Only if | D．Even if |
There has been a great increase in bicycle sales this year________?
| A．does there | B．isn’t there | C．hasn’t there | D．isn’t it |
Many people like white color as it is a ________ of purity.
| A．symbol | B．sign | C．signal | D．example |
All the teachers are against the idea to ________the new teaching building beside the sports ground.
| A．find | B．set | C．locate | D．build up |
An old friend of mine called me up this morning,but he refused to tell me his present ________.
| A．home | B．place | C．where | D．whereabouts |
Mr Hiward,a man ________himself Dan came to see you this morning,and left you a message here.
| A．called | B．calling | C．was called | D．calls |