下列化学用语中，既能表示宏观意义，又能表示微观意义的是（    ）

根据句意及首字母提示完成单词
We went to a summer c____ last year.
There w____  many trees on the mountains five years ago(以前).
We are studying hard for e____ .
—He was an English teacher.—R____ ?  Did he teach you?
What an a____  classroom!  It’s too dirty!