洋地黄中毒引起的最严重后果是（）
A.神经系统损害
B.严重心律失常
C.肾功能损害
D.肝功能损害
E.难治性心力衰竭
参考答案：B
Sybase是世界上第一个真正的基于client/server结构的RDBMS产品。 ( )
Because it was snowing hard, buses could _________ get through, _____did taxi appear on the street.
A．both; and
B．either; or
C．not only; but also
D．neither; nor
