is hard is to do good all one’s life and never do anything bad.
—The research on the new flu virus vaccine is challenging and demanding. Who do you think can do the job? —________ my students have a try?
I ________ him in time, otherwise he would have fallen off the bike.
The project was carefully planned, or a great deal of money ________.
—How dangerous it was! —Yes, but for the passerby's quick action, the girl ________.
Martin hasn't got in touch with me for ages. He ________ my new cell phone number.