题目如图1。两枚同样大小的硬币,其中一个固定,另一个沿其圆周滚动,滚动时,两枚硬币始终保持有一点接解,则滚动硬币再回到原来位置时,它自转的周数为( )．(A)1 (B)2 (C)3 (D)4这是山东省济南市2000年的一道中考题,提供的标准答案是(B)．文[1]给出的答案也是(B)．并且文[1]从该题出发,将硬币改成圆环,固定圆A与滚动圆B The title is shown in Figure 1. Two coins of the same size, one of which is fixed and the other is rolling along its circumference. When rolling, the two coins always have a certain degree of connection. When the coin is rolled back to its original position, the number of revolutions is (). (A)1 (B)2 (C)3 (D)4 This is an examination question in 2000 in Jinan City, Shandong Province. The standard answer provided is (B). The answer given in [1] is also (B). And [1] proceeded from this question by changing the coin into a ring, fixing the circle A and the rolling circle B