Each of the students in Grade Nine looking forward to a good result in the senior middle school entrance exam. Just work hard, then your dream will come true.A. is ,have B. are, having C. is, having
—People have realized how important the environment is, but still trees ____in the world every year. — We must do something to stop it.
Do you know _____?
There is _____ knocking at the door. Go and see who it is.
—What was your hometown like five years ago? —It _____ very old and dirty.
I won’t take part in the party _____ Joe invites me..