丝状菌的大量出现意味着要发生活性污泥膨胀或进水水质变差（）
查看答案
Nancy: May I see your driving license and vehicle registration card, please？Dick: ______.
A. Sorry, I forgot to bring my homework.
B. Sure. Here is my business card.
C. Good. Did I do anything wrong？
D. Yes. But I don't think I am a good student.
水样中汞测定的常用方法有冷原子吸收法和双硫腙分光光度法（）
微信支付 
支付宝支付