30()
A. the
B. an
C. did
D. had
The people in the room laughed at Richard because ()
A. he wasn't polite
B. he wasn't clever
C. he held the newspaper upside down (颠倒)
D. the newspaper was yesterday's
21()
A. is
B. has been
C. was
D. had been
半效杀菌剂
A. 乙胺丁醇
B. 利福平
C. 吡嗪酰胺
D. 强的松
E. 环磷酰胺