—Are they ______ books?

—No, they aren't. They're ______ books. [ ]

A. you; they

B. your; he 　　

C. your; her 　

D. your; she

正常生产巾，如减压水封破坏主要由（）造成的。

A.水封罐“U”形管顶破虹吸未开或堵塞

B.排水阀失灵

C.塔顶温度太高

D.水封罐放大气管线堵塞或存油冻凝