以下哪些不宜做电复律（）。

A.阵发性室性心动过速

B.低血钾

C.洋地黄中毒

D.室颤

E.以上均不是

My father warned me _____ going to the West Coast because it was crowded with tourists.[ ]

A. by  

B. on

C. for  

D. against