_______, the experiment will be successful.

A. If carefully doing B. If it done carefully

C. If carefully done D. If doing carefully

It makes _______ big difference to keep calm when giving _______ first aid.

A. a, / B. /, the C. a, the D. /,a

This word is wrongly spelt；a letter is _______.

A. left behind B. left alone C. left out D. left off

You must keep it _______ in mind that education is the first productivity.

A. mildly B. firmly C. tightly D. roughly

The maths teacher demanded that all the students _______ the examination paper within one and a half hours.

A. would finish　B. finished C. finish　 D. could finish

Busy _______ he was, he managed to spare some time to help plan the project.

A. while B. although C. as D. when

Giving up smoking is a slow and painful _______ for him.

A. pressure B. process C. motivation D. profession

The number of people present at the meeting _______ two hundred and a number of them _______ from the countryside.

A. is, are B. is, is C. are, are D. are, is

With a lot of difficulties _______, they went to the seashore and had a good rest.

A. settled B. settling C. to settle D. being settled

Carelessness always contributes _______ car accidents. Therefore, drivers are advised to concentrate their attention _______ driving.

A. for; to B. to; on C. with; on D. in; to