化学与环境、材料、信息、能源关系密切，下列说法正确的是
| A．导致青岛开发区石油管线爆炸的非甲烷总烃在日光照射下会产生光化学烟雾 |
| B．塑化剂是一种应用很广的化工塑料软化剂，可大量添加到婴幼儿玩具中 |
| C．航天员太空实验能够证明水分子组成和结构在太空中发生改变 |
| D．汽油标准已由“国Ⅲ”提到“国Ⅳ”，这意味着汽车不再排放氮氧化物 |
His sister left home in 1998, and _______since. 
| A．had not been heard of | B．has not been heard of |
C．had not heard of | D．has not heard of |
What do you mean, there are only ten tickets? There _____ be twelve
| A．should | B．would |
C．will | D．shall |
Could I speak to ______ is in charge of International Sales please?
| A．who | B．what |
| C．whoever | D．whatever |
How much _______ she looked without her glasses!
| A．well | B．good | C．best | D．better |
Let’s go to ______ cinema – that’ll take your mind off the problem for _____while.
| A．the; the | B．the; a | C．a; the | D．a; a |