要想观察血液中的红细胞，可以将实验材料制成切片进行观察。
A型
B型
价格（万元/台）
8
6
月处理污水量（吨/台）
120
100
I'm waiting for my friend. If he _______, I will go swimming alone.
— She didn't finish my homework _____ my father came back.
— So you went to bed too late.
