Smart phones are more and more popular now.—So they are. But they still ________ too much.

Please write an invitation _____ the cinema.[ ]

Four dollars a pair? I think it’s a bit too much.— If you buy three pairs, the price for each will _______ to three fifty.

Excuse me. You shouldn’t smoke here. Look at the sign “NO SMOKING HERE”.–Sorry, I ________ it just now.

There is ______ “f” and ______”u” in the word “four”.