— Are you still thinking about the email Tony sent you yesterday? 

— Oh, to tell the truth, that's _____ makes me feel excited. [ ]

A. What

B. how

C. that

D. why

下列不属于梅毒实验室诊断方法的是

A．血清不加热的反应素试验

B．VCRL试验

C．胶体金试验

D．快速血浆反应素环状卡片试验

E．墨汁试验