He made another wonderful discovery, ______ of great importance to science.
| A．which I think it is | B．which I think is |
| C．which I think | D．I think which is |
Scotland liesthe north of England, it isof Britain.
| A．to; part | B．on; the part | C．in; part | D．to; the part |
When lastvaluable, those books enjoyed great success.
| A．finding | B．found | C．being found | D．to be found |
He knows little of mathematics, of chemistry.
| A．and still less | B．as well as | C．and still more | D．no less than |
Discovering consists of seeing what everybody has seen andwhat nobody has thought.
| A．think | B．thinking | C．thought | D．to think |
—Did the policeman let you in?—No, I told him who I was.
| A．if | B．once | C．as though | D．even though |