You will be late ________ you leave immediately.[ ]

The teacher encourages us todiscussions at the English corner.

How cool you look in this shirt! How much did you ______ on it?—Not very expensive. It’s just one hundred yuan.

What do you think of the book?　-Oh, excellent. It is worth _____ second time.

Our government ______ all people to save energy and fight against pollution.