We don’t need a lot of friends _______ they are good.
Do you know a spaceship flies at about nineteen kilometers ________ second?
— Morning, boys and girls! Please try your best in today’s exam! Good luck to all of you!— ________
—Sir, could you please put out your cigarette? This is a smoke-free (无烟的) school.—______
—How often do you chat with your friends online?— . I'm busy with my study.
the children have fun, parents can take dance lessons on the beach.