_________ the temperature might drop, coal was prepared for warming.

We must know what we should do and what we should avoid _______ a good impression on others in public places.

I will always remember _____ to the star’s concert and what I experienced there.

____all the required papers. he didn't answer the questions fluently in class.

"The president's report," a smile on his face, he continued, "___ to several hot topics, discusses how to increase peasants' income．"

The boy seated himself in the corner with his back       to his father.

The little baby, if _________ by other people, will wake up and cry.

Finding her car stolen, ______ .

The living room is clean and tidy, with a dining table already_____________ for a meal to be cooked.

Professor White has received a letter ___ to give a lecture in Peking University.