if we take short breaks__.19. Food in small pieces could be eaten easily from the sun twigs which_ turned into chopsticks.20. Walls make of adobe take in the heat from the sun on hot days and give out that heat_ during cool nights， thus warning the house.21. …
【重点词组】1. invite sb. to do sth.邀请某人做某事2.one of +形容词最高级+ 名词复数3. say thanks/hello/sorry/good-bye to sb.向某人致谢/问好/道歉/告别4.
