Teacher:We all know that beat causes an object to expand an cold cauese it to contract.Now,can anyone give me a good example?
老師:我們都知道熱脹冷縮的道理.現(xiàn)在,誰(shuí)給我舉個(gè)例子?

John:Well ,in the summer the days are long,and in the winter the days are short.
約翰:嗯,在夏天天都長(zhǎng),在冬天天都短.