He tried his best to solve the problem, _______ difficult it was.
| A．whatever | B．however | C．whichever | D．wherever |
His glasses, ________ he was like a blind man, fell to the ground and broke.
| A．which | B．from which | C．with which | D．without which |
In the office I never seem to have time until after 5:30 p.m.,____ many people have gone home.
| A．whose time | B．that | C．on which | D．by which time |
Great changes have taken place in that school. It is no longer ___ it was 20 years ago, ___ it was so poorly equipped.
| A．what, when | B．that, which | C．what, which | D．which, that |
He was educated at a local grammar school, ___ he went on to Cambridge.
| A．from which | B．after that | C．after which | D．from this |
She ___ for the professor who was ill.
| A．substituted | B．changed | C．shifted | D．replaced |