I’m sorry I stepped on your foot; it was an accident.—It wasn’t! You did it ______________ .

People believe thatmutual understanding _______ a happy marriage

________ a difficult situation, so you should send hima message and give him some advice.

If pupils play video games too often,they will become addicted to them, thus________their schoolwork. [ ]

The room is empty except for a bookshelf _____ in onecorner.