—What made her so happy?—_____ her son passed the driving test.
It took a long time for the connection between body temperature and illness ___________.
Work gets done __________ when people do it together and the rewards are higher too.
24.—I don’t think I need to buy that toy penguin—it’s for kids.—__________you don’t have kids, buy it anyway because it looks good.
—Have you worked here since you graduated?—No, I ____________at a factory in Beijing for six years.
—Who is making so much noise in the garden?—___________ the children.