There are eight tips in Dr.Roger's lecture on sleep，and one of them is：________ to bed early unless you think it is necessary.

Not until I read your letter ________ the true state of the affairs.

________ going to the program If You Are the One，she knew she had to be there or her mother would be unhappy.

He ________ your car by mistake because he didn't have the keys.

Professor Tang didn't give us a speech today.It was ________ he had a traffic accident on the way to school.

She often shares her deepest thoughts and fears with friends through QQ, as if they ________ chatting in her living room.

I ________ him in time, otherwise he would have fallen off the bike.

People love the  convenience of bottled water, but if they ________ the problem it causes, they ________ try carrying water in a reusable steel container instead of plastic.

—How was your trip to Yancheng last week?
—Wonderful! I only felt sorry that I ________ the nature reserve of red­crowned cranes, but the weather was awful.

If I ________ your advice then, I think that the crops could be growing better.