When you have_____test,you must be careful all______time 。A. a;/ B. a;the c. an;a
People should _________ down trees in order to protect the environment.
He has read_________ many books _________ he knows a lot about the world.
John with his parents _________ been in Australia for about two years.
I’m afraid that no one knows_________ .
I still remember the first park_________ I visited in my life.