经土壤传播的意义大小,取决于()
A.病原体在土壤中的存活时间
B.易感者与土壤的接触机会
C.个人卫生习惯
D.A、B、C均不是
E.A、B、C均是
参考答案:E
香加皮中含
A.木脂素类
B.强心苷类
C.生物碱类
D.C21甾苷类
E.4-甲氧基水杨醛
The famous director Li’an failed many times but he eventually _____ to achieve success.
A.broke up
B.broke off
C.broke through
D.broke away