Don’t you know you are teaching the fish to swimThey are all grow-ups.

Must I turn off the gas after cooking ?–Of course You can never be ___ careful with that

How about your journey to Mount Tai ? —Everything was wonderful except that our car ____twice on the way.

The teacher rather than the students _____ referring to Reading Skills that _____newly published in America.

If the boy had _____ the dog alone, it wouldn’t have bitten him