患儿，5岁，低热、咳嗽，昼轻夜重，而且呈阵发性痉挛性咳嗽，偶有特殊的“鸡鸣”样吼声。该患儿直接对着鲍—金平板咳嗽，于37℃培养2～3天后出现百日咳杆菌样的菌落，而且可与百日咳杆菌免疫血清发生凝集反应。不过此菌落常发生S—R型变异，有荚膜毒力强的菌株。此菌属于（）

A.Ⅰ相

B.Ⅱ相

C.Ⅲ相

D.Ⅳ相

E.Ⅱ、Ⅲ、Ⅳ相

—Was it because of his short­sightedness ________ he was turned down by the company?

—No, it was because of his poor performance.

A．when

B．that

C．what

D．how