吸气时,膈肌舒张,膈顶部下降,使胸廓的上下径增大.(判断对错)
正方形每相邻的两条边互相____。
—Peter, please ask Tom to my office as soon as he _______ back tomorrow.
—OK, I will.
①都易溶于水
②都可以灭火
③通常情况下密度都比空气大
④都能与石灰水反应
⑤都是无色气体
⑥都有三态变化.