He managed to reach the summit of his career, but it was at the _________ of his health.

A．consumption

B．credit

C．exhaustion

D．expense

关于神经纤维静息电位的形成机制与下列因素不相关的是（）

A.细胞外K⁺浓度小于细胞内的浓度

B.细胞膜主要对K⁺有通透性

C.细胞膜主要对Na⁺有通透性

D.细胞内外K⁺浓度差加大可使静息电位加大

E.加大细胞外K⁺浓度，会使静息电位减少