This robot is supposed to save a lot of labor, but it remains a problem if it ______.

We have friends all_______ the world.[ ]

My favorite animals are koalas. They usually sleep _____ the day, but _____ night they get up. [ ]

Is your math book on the desk, Tommy?—No, it isn’t. It’s _______.[ ]

______ will he stay in Beijing?—For a week.[ ]