Do you know if he _______ to play basketball with us?–I think he’ll come if he __________ free tomorrow. [ ]

What on earth are the police busy with?—They have been looking into how the plane crash _______.

Do you know_______ this dictionary belongs to? -Let me see. Oh, it’s_______.

You must return these books ________ next Monday, or you will be fined. [ ]

I’d like you to tell me something about Shennongjia. -I’m sorry, but neither Jack nor I ________ there.