One is never _____ old _____ learn. Do you think so?—Yes. I agree.[ ]

I have been in this school______1988.[ ]

Time is money.—But I think time is _________ money.

They want to develop a kind of dog-friendly food _________ will help dog owners cool down their pets.

How do you like these two books? —___________ of them are interesting. I want to read them again.