Question

求解两道英语题，要详解。 如图，27和30，30题解释下四个选项具体意思。

Answer 1

My voice was so little and the shop owner had to bend down to hear what it was that I wanted to buy.
我的声音是如此的小以至于店主要弯下腰才听得见我想要买什么。
宾语从句属于复合结构，it作形式宾语，that引导真正宾语，此处that不可省略。

PM2.5, which indicates the condition of air pollution is a professional term.
PM2.5是一个指示空气污染状况的专业术语。
number 数字 term 术语 mark 记号 signal 信号

Answer 2

27 分析不会，靠语感选吧
30 a数字，b术语，c标记，d标志