挥发油中主要含有的萜类化合物是
A．单萜
B．倍半萜
C．二萜
D．三萜
E．二倍半萜
参考答案：A,B
My father moved to Hainan in _____, when he was in ______.
A．the early 1990s; his thirties
B．early 1990s; his thirties
C．the early 1990’s; his thirty
D．early 1990’s; his thirty
声带息肉的临床表现和治疗方法是什么?
