Don’t give up halfway, Andy. You’ll succeed _______ if you keep on working like this.
Which materials can be thrown into the sea _______on the nature of them?
We should give students more chances to _______ the problems in their daily lives.
— I heard they went skiing in the mountains last winter. — It ___ true because there was little snow there.
It was a bad year for films, _______ both quantity and quality.
— Where is Mr. Wang?— He is not here. He must _______ the students’ papers in the office.