目前已知的最强的致泻毒素是（）。
A.Vero细胞毒素
B.霍乱肠毒素
C.耐热性肠毒素
D.不耐热性肠毒素
E.气单胞菌不耐热性肠毒素
参考答案：B
---Nowadays children are bearing too heavy a learning burden.
---______. So much homework do they have to do that they almost have no time for other activities.
A．So what?
B．It cannot be better
C．Good idea
D．I cannot agree more
散苗工作应当在苗木栽植前的1～2天完成，以保证工作进度。( )
