学进去

Three things are necessaries (必需) for us to keep alive (活着). They are air (空气),_____ and food (食物). We eat food twice (两次) or three times a day. We drink water several times (几次) a day. We breathe (呼吸) day and_____. If (假如) a man doesn’t have any food and doesn’t drink_____, he can live (活) about three_____. But if a man doesn’t breathe, he can keep alive for only about three minutes (分钟). So we see that breathing is even more important than drinking, and drinking is more important (重要) than_____.