在一定温度下，饱和汽的分子数密度是一定的，因而饱和汽的压强也是一定的，这个压强叫做这种液体的____．未饱和汽的压强____饱和汽压．

①中淡黄色的是____

②中含有的血细胞是____和____

③中含有的血细胞是____，其作用主要是运输____．

    Mr Jones and Mr Brown work in the same office. One day Mr Jones says to Mr Brown, “We want to  have a small party at our house next Wednesday evening. Do you and your wife want to come ?”

    Mr Brown says, “Thank you very much. I must phone my wife and ask her.” So Mr Brown goes to the other room and makes a telephone call. When he comes back, he isn't happy.

    “Why are you not happy?” asks Mr Jones, “Do you speak to your wife?”

    “No, She isn't at home. My little son answers the phone. He says she is looking for him outside(在外面) .”

下图为DNA分子在不同酶的作用下所发生的变化，图中依次表示限制性内切酶、DNA聚合酶、DNA连接酶、解旋酶作用的正确顺序是