第n个数是n2n+1.
心肌细胞中传导速度最慢的是
A.心房肌
B.心室肌
C.房室交界区
D.左、右束支
E.浦肯野纤维
Everybody knows that the sun ____ in the east.
A.raises
B.is raised
C.rises
D.is risen