秤的计量性能主要包括灵敏性、鉴别力、鉴别力阈、耐久力（）和重复性。
参考答案：稳定性
–Has your father returned from Africa yet?
–Yes, but he _____here for only three days before his company sent him to Australia.
A．has been
B．will be
C．would be
D．was
票据权利是双重请求权，持票人行使票据权利时，具有可选择性。( )
