For the reason why optical activity of mesomer is counteracted classical answer was not convincing.

指体因传统解释不合理性。

For the reason why optical activity of mesomer is counteracted classical answer was not convincing. By use of the helix theory and stable staggered conformation answer can be obtained.

指体因传统解释不合理性。利用螺理论和稳定交叉式构象，合理地解释体因。