He felt______as soon as he realized that he had asked a foolish question.

____your own needs and styles of communication is as important as learning to convey your affection and emotions.

—Please go on with your demonstration．—But where was I?—Well, you_____the two chemicals together．

The house caught fire last week, with little of the original building _________.

Technology is developing so rapidly that   for only a year , my cellphone is out-of-date .