变压器从高压侧引分接头是为了（）
A、焊接分接头方便
B、高压侧电流小
C、分接开关的截面可以小一些
D、发热的问题容易解决
参考答案：A, B, C, D
心尖区闻及隆隆样舒张期杂音，应考虑为（）
A.二尖瓣关闭不全
B.主动脉瓣关闭不全
C.二尖瓣狭窄
D.肺动脉瓣狭窄
E.三尖瓣狭窄
—I want to return the book to Jack, but I can't find him.
—He _____ the library. You can find him there. [ ]
A. has been to
B. has gone to
C. has left
D. went to
