—I don't know. Maybe the traffic is heavy(交通拥挤).
A:this
B:that
C:it
D:he
如图是我国古代数学家赵爽在为《周髀算经》作注解时给出的“弦图”,它解决的数学问题是 ____
下列图中线圈中不能产生感应电流的是( )