Jumping out of_______________airplane at ten thousand feet is quite _______________ exciting experience.
| A．/; the | B．/; an | C．an; an | D．the; the |
In South-East Asia, many farmers cannot afford _____ farm equipment such as tractors, so most of the work is done with human labour.
| A．considerate | B．conventional |
| C．confidential | D．correctional |
The first thing you must remember is that in order to succeed, it is almost compulsory that you ______ optimistic.
| A．be | B．are | C．must be | D．have been |
John can finish this task quickly ______ using better methods.
| A．on | B．in | C．by | D．at |
It may be necessary to stop _____ in the learning process and go back to the difficult points in the lessons．
| A．at intervals | B．at random |
| C．at ease | D．at length |
The driver stopped his car so _____ that he was hit by the cab right behind him．
| A．impolitely | B．violently |
| C．abruptly | D．cautiously |