Yesterday was my friend Bruce’s birthday. He invited me ______ his birthday party.[ ]

Frank，you look worried．Anything wrong?Well，I ______a test and I’m waiting for the result．

It’s important ______ you to learn English well.[ ]

There is _______ “u” and _______ “s” in the word “use”.

I know nothing about the history of the telephone. Could you tell me ?— Yes, in 1876