Our bad living habits will destroy the earth. Only by changing ____ we live can we save the earth.
I arrived home at midnight, _______ my parents had been waiting for nearly three hours.
--- It’s wrong of a student to follow ______ his teacher says. --- It’s true. I can’t agree ______.
The teacher set such a difficult problem ________none of us could solve.
If we want ______much cleaner world, we should reduce _______ emission of carbon dioxide.
This morning my mother told me _____ she would attend a wedding party _____ she wouldn’t come back home for lunch.