He is often late for class, ____ always makes the teachers unhappy. [ ]

A. what

B. which

C. that

D. it

下述ARDS要点，哪项不对（）

A.败血症是最常见原因

B.临床表现与影像改变同步

C.特征性影像表现比临床症状迟

D.早期，间质性肺水肿

E.可有左心衰