—How much is too much for a schoolbag?—Experts say students should carry_______ more than 10 or 15 percent of their body weight.
----- I’m taking my driving test tomorrow. ----- _____!
Some insects_____ the colour of their surroundings (环境) to protect themselves.
_____ is known to everybody, the moon travels round the earth once every month.
We are invited to a party _________in our club next Friday.
It sounds like something is wrong with the car’s engine. ______ , we’d better take it to the garage immediately.