–  Bad luck! The car breaks down again. I wish I knew about car repair.

________ you learn? Courses are offered at Seamine College.

________. I wonder when courses begin.

A．Why don’t; That’s a good idea

B．Did; That’s reasonable

C．Why don’t; I don’t care for it

D．Did; Your idea sounds very encouraging

髌骨软骨软化症的病理改变是（）

A.最早发生于软骨深层

B.最早发生于软骨表层

C.最早发生于软骨边缘

D.最早发生于滑膜

E.最早发生于半月板