铅蓄电池属于（）次电池，其充电过程和放电过程是一种（）的电化学反应。
参考答案：二，可逆
-- Is it necessary that he ____ to London but to New York?
-- I think so, but the problem is ____ he has refused to.
A．will not be sent; that
B．not be sent; that
C．should not be sent; what
D．should not sent; what
孕8个月，无痛性 * * 流血，首先应考虑()
A．输卵管妊娠并出血
B．前置胎盘
C．胎盘早剥
D．葡萄胎
E．先兆流产
