单项选择题

It is difficult ()a world record and even more difficult to () it.

A. keeping, set
B. keep, set
C. set, keep
D. to set, keep

相关考题

We should always () our opinion () facts.A. base ... in...

单项选择题We should always () our opinion () facts.

A. base ... in
B. base ... on
C. basis ... in
D. basis ...on

The game will take place ()June 2nd.A. onB. atC. inD. d...

单项选择题The game will take place ()June 2nd.

A. on
B. at
C. in
D. during

So far there is no proof () spaceships from other plane...

单项选择题So far there is no proof () spaceships from other planets do exist．

A．which
B．that
C．how
D．what