．We are going to ______ with some friends for a picnic . Would you like to join us?

There are fiftystudents in our class, ______ are girls .

I didn’t know _______.He looked so sad yesterday.-Maybe he failed his exams.

Are you satisfied with her work, sir?—Not at all. It couldn’t be any _______.

We can deal _______ our problems by ________ them as challenges.