慢性菌痢
A．病程超过2周B．病程超过1月C．病程超过2月D．病程超过半年E．病程超过1年
参考答案：C
_____ the morning of December 1st, 2006, the 15th Asia Games _____ in Doha (多哈). [ ]
A. In; held
B. On; was held
C. At; held
D. For; were held
提取分离木脂素类成分时，应该注意什么问题？
