. One of the students hasn’t prepared lessons very well.
| A．his | B．one’s | C．ones | D．their |
Fred entered without knocking and, very out of breath, sank _______ a chair.
| A．on | B．off | C．into | D．to |
People try to avoid public transportation delays by using their own cars, and_____ this creates further problems.
| A．in short | B．in case | C．in doubt | D．in turn |
Scientists are convinced_____the positive effect of laughter_____physical and mental health.
| A．of; at | B．by; in | C．of; on | D．on;at |
This is a junior school.You should go to a senior school _____girls of your age.
| A．for | B．about | C．from | D．to |
I saw a woman running toward me in the dark.Before I could recognize who she was，she had run back in the direction______ she had come.
| A．of which | B．by which | C．in which | D．from which |