She writes a letter to her pen pal onec a month.(改为否定句)

问题描述:

She writes a letter to her pen pal onec a month.(改为否定句)

她每月给她的笔友写一封信
(原句中有个小错误 "onec a month"应该是"once a month")

She doesn't write a letter to her pen pal once a month.