Scientists are convinced _______the positive effect of laughter ______ physical and mental health.
Most of __________we call geniuses (天才)are successful only because they have made extraordinary efforts.
—Did you get my letter? —I received one just as I__________.
When she called at his studio, she__________that he had gone to Japan.
Robert made a call to his parents yesterday afternoon. To his disappointment, __________of them answered it.
I __________stop by sometime and thank her for all her help.