—Shall I attend my friend's comingofage ceremony, Mum?—No, unless you see to ________ that you will be home before 10:00 P.M.
Knowledge from real life isn’t easier to forget than __________ achieved from textbooks.
In our city there are several big public parks __________ many people can go to enjoy the beautiful scenery.
Most of the inhabitants (居民) can’t afford to buy houses of their own, because the price is rising __________.
__________ most efficient way to understand thousands of new words is to gain __________ good knowledge of basic word formation.
—Can you help me with the math problem, Dad? ___________.—OK, let me think it over.