-Where are the English books? ---Sorry, ___.A I know B I don’t know C it isn’t D they’re not
I don’t know if he tomorrow. If he , I’ll tell him about it.
We can’t work out the physics problem. Can you tell us ____?
This question sounds _____ than that one.
Health is very _____and every student knows the _____of keeping healthy.
Our country _______ a lot in the last fifty years.