—What color is the ruler? —_____A.It's a blue ruler.B.It's a blue.C.It is blue.
—Could you tell us _______? —About five minutes.
Thank you for giving us some useful advice _______ how to deal _______ the problems.
Things made of plastic are usually _______, but they are _______ to get polluted.
All the club members _______ the floor when they heard someone _______ for help.
A fridge is used to keep food which goes _______ very _______.