People are deeply struck by Forrest Gump because of his unselfish _______ to helping others.
| A．devotion | B．invitation | C．expression | D．protection |
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 |
None of the students in the class likes the professor， who is used to being _____ of everything they do．
| A．optimistic | B．criticaL |
| C．interested | D．emotional |
Africa is a very _____ continent， with each country， or even each part of a country having its own unique culture．
| A．diverse | B．abstract | C．remote | D．vacant |