【提出问题】用红磷燃烧的方法为什么测出的氧气含量远低于21%？
study，I，grandparent，make，newspaper
根据短文内容，用方框中所给单词的适当形式填空，并将答案写在相应的横线上。每词限用一次。
Hi, I'm Laura. Today is Sunday. My family are at home. What are they doing now? Let me tell you. My ____ are watching a movie. They like CCTV News very much. My father is reading a ____ about sports. My mother is ____ soup in the kitchen. Steve is ____ brother. Look! He is ____ English on the computer.
2AB(g)达到平衡状态的标志是（ ）
2Z,达到平衡后，测得平衡时混合气体的总物质的量是开始时混合气体物质的量的0.7倍，则Y的转化率最接近于（ ）