The joy of life is a deep spring. Only when digging deep ______ clear and sweet water.

If you don’t want to fall behind others, you must _____ current events.[ ]

Do you mind if I turn on the air-conditioner —___________. I feel a bit hot.

As the train was to pull out, her husband came running along and climbed ________.

There _______an important meeting next week, isn’t there