目前对睾丸固定术的时间选择是()
A．1岁之前
B．2岁左右
C．5岁
D．入学前
E．尽可能得早
参考答案：D
There______ great changes in our country since 1979. [ ]
A. have been
B. were
C. has been
D. are
高钾血症的心电图表现为（）
A.T波高尖-T间期延长RS波增宽
B.P-R间期延长RS波增宽
C.P-R间期缩短RS波增宽
D.ST段明显抬高
E.U波增高T段下移波低平或倒置
