在线圈两端自感电流的方向是由（）流入线圈的。
A.正极
B.负极
C.正极或负极
D.两端
参考答案：B
It took a long time for the connection between body temperature and illness________.
A．to make
B．to be made
C．making
D．being made
上尿路结石出现血尿的特点是
A．活动后血尿
B．初始血尿
C．终末血尿
D．无痛性血尿
E．全程血尿
