You can come here to ask me ________ if you have any questions.
A.at one time | B.at a time | C.at any time | D.all the time |
The most impressive sight in China,one of the wonders of the world,_____ the Great Wall.
A.is | B.are | C.was | D.were |
The factory used 65 percent of the raw materials,the rest of whichsaved for other purposes.
A.is | B.are | C.was | D.were |
—Why does the lake smell terrible?
—Because large quantities of water_______________.
A.have polluted | B.is being polluted |
C.has been polluted | D.have been polluted |
One-third of the country____covered with trees and the majority of the citizens_______black people.
A is;are B is;is C.are;are D.are;is
Was it not until you began to work —— how much time you had wasted?
A.did you realize | B.that you realized | C.did you not realize | D.that you didn’t realize |