There ________ great changes in Zhangzhou since 2010.A. have had B. has been C. have been
—Ann has finished her homework, hasn’t she? —Yes. She _____ it an hour ago.
—Is your brother at home? —No. He ________ the library. He hasn’t come back yet.
We know that about seventy percent _____ the earth _____ covered by water.
you drive,you will be.
The policeman asked the child ________ cross the street ________ the traffic lights turned green.