Only after the woman had her own child how difficult it was to be a mother.
| A．did she realize | B．she had realized | C．she realized | D．had she realized |
______ of the land in that district ______ covered with trees and grass.
| A．Two fifth…is | B．Two fifth…are | C．Two fifths…is | D．Two fifths…are |
Books of this kind ______ well.
| A．sell | B．sells | C．are sold | D．is sold |
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 |