若y=2x+1，当x（ ）时，y<x。
<-1
---- Do you know _______ they got to know each other?
---- It was last year_______ they both taught Chinese in Scotland.
A．When it was that, when
B．when it was that, while
C．When it was that, that
D．When it was that, as
罹患率适用于（）
A.慢性病
B.疾病的长期流行
C.较小范围或短期流行
D.某病的隐性感染
E.时间以年为单位进行统计
