Abstract: This paper reexamines the issue discussed on the paper titled "Are the electric and magnetic fields of plane electromagnetic waves in free space always in phase?" in College Physics. The results demonstrate that the viewpoint suggesting possible phase opposition between the electric field intensity E and magnetic field intensity H in plane electromagnetic waves is unnecessary. There is no essential difference between the "synchronization" and the same phase, confirming that the traditional viewpoint presented in textbookswhich maintains that the electric and magnetic fields of plane electromagnetic waves in free space are always in phaseholds true without exception.

Key words: electromagnetism, plane electromagnetic waves, in phase, phase opposition