He made another wonderful discovery, ________ of great importance to science．

A．which I think is

B．which I think it is

C．which I think it

D．I think which is

I live in the house with its door ________ to the south．

A．facing

B．faces

C．faced

D．being faced

－When did it begin to snow?

－It started ________ the night．

A．during

B．by

C．from

D．at

________ the temperature might drop, coal was prepared for warming．

A．To consider

B．Considered

C．Considering

D．To be considered

“Goodbye, then,” she said, without even ________ from her book．

A．looking down

B．looking up

C．looking away

D．looking on

－What does the sign over there read?

－No person ________ smoke or carry a lighted cigarette, cigar or pipe in this area．

A．will

B．may

C．shall

D．must

Tony Blair played ________ violin in a band at university．He gave that up to ________ lawyer and then entered politics．

A．the; become

B．/; become a

C．the; turn

D．/; turn a

It was after he got what he had desired ________ he realized it was not so important．

A．that

B．when

C．since

D．as

It was in Beihai Park ________ they made a date for the first time ________ the old couple told their love story．

A．that; that

B．where; when

C．that; when

D．where; that

－When do we need to pay the balance?

－________ September 30．

A．In

B．By

C．During

D．Within