1. —What have you been recently?　　—I _______ in Hangzhou on business for a week last month.　　A. have beenB. wasC. ......

数字高压断路器具有无磨损、精度高、寿命长等优点.但某些部件的失效也会给电力系统及用户带来重大损失.为了提高断路器的性能和可......

一定的贫富差距在我国现阶段具有客观性和合理性.对于这种社会现实我们的可容忍力与现实容忍力十分不相称.为矫正这种差异就要通过......

Making of errors is an inevitable and indeed necessary part of the learning process.We should have positive attitude tow......