Why do you look sad—There are so many problems ______.

Will you please help me _____ the exercise books to the students?— Sorry I have been in a race and my strength has completely _____.[ ]

It’s said that an American often starts a speech witha joke, _______ a Japanese seldom does.

In communication, a smile is usually________ strongsign of a friendly and ________ open attitude.

My father works in a ________．His students like him very much．