—Why are the two students standing at the gate of the teachers'office?

—They________to each other in class and________.[ ]

A. have whispered; are punishing

B. had whispered; were punished

C. whispered; are being punished

D. are whispering; were being punished

Graves病最主要的发病机制是（）

A.长期碘摄入不足

B.长期碘摄入过多

C.各种因素致下丘脑分泌TRH过多

D.各种原因致垂体分泌TSH过多

E.遗传易感性和自身免疫功能异常