Only ________ according to the directions can the medicine be quite effective.

—We didn't find the Blacks ________ the lecture.
—No one had told him about ________ a lecture the following day.

A few days after the interview，I recevied a letter ________ me admission to the university.

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

________ as the “first lady of speech”，Dr, Lillian Glass is recognized as one of the world's leading experts on communication skills.

John received an invitation to dinner，and with his work ________，he gladly accepted it.

—Come on，please give me some ideas about the project.
—Sorry.With so much work ________ my mind，I almost break down.

The country has already sent up three unmanned spacecraft，the most recent ________ at the end of last March.

________ the program，they have to stay there for another two weeks.

________ for several weeks，the city needed food.