单项选择题
A．Two to four months. B．About three weeks. C．At least half a year. D．Two years or more.
A．She has to post a letter instead. B．She has to turn down the man’s request. C．She’s not sure if the computer is fixed. D．She can’t send the message right now.
A．He needs another job as research assistant. B．He asked Professor Williams for assistance. C．He assists Professor Williams with his teaching. D．He is doing research with Professor Williams.