it was because of his kind nature _______I fell in love with Peter.

A．before

B．when

C．that

D．since

视网膜色素变性（如图）的眼底典型改变是（）

A.视网膜血管硬化

B.继发性视神经萎缩

C.原发性视神经萎缩

D.视网膜骨细胞样色素沉着

E.以上都不对