People develop __________ preference for a particular style of learning at __________ early age and these preferences affect learning.
| A．a; an | B．a; / |
| C．/; the | D．the; an |
Professor Smith, along with his assistants,____ on the project day and night to meet the deadline.
| A．work | B．working | C．is working | D．are working |
_____ of the land in that district _____ covered with trees and grass.
| A．Two fifth; is | B．Two fifths; are | C．Two fifth; are | D．Two fifths; is |
The company had about 20 notebook computers but only one-third _______ used regularly. Now we have 60 working all day long.（2006浙江）
| A．is | B．are | C．was | D．were |
The country life he was used to ______ greatly since 1992.
| A．change | B．has changed | C．changing | D．have changed |
The number of people invited ______ fifty, but a number of them _____ absent for different reasons.
| A．were, was | B．was, was | C．was, were | D．were, were |