He said it was this classroom _______ he found his lost watch and _____ he would take good care of it from then on.

A．where; /

B．when; what

C．that; what

D．where; that

关于生态学研究说法错误的是（）

A.常应用常规资料或现成资料，节省时间、人力和物力

B.可以确定两变量之间的因果联系

C.容易出现生态学谬误

D.可估计某种疾病发展的趋势

E.对病因未明的疾病可提供病因线索供深入研究