单词辨析worry ,worriedhe is worried about his son一句中为什么不用worry而用

单词辨析worry ,worriedhe is worried about his son一句中为什么不用worry而用 worry是一个动词,但为什么常用be worried about而不用worry about is the old man （ ） about his son?应该填 worry worried 还是worries 是“He often worry about his son's studies"还是“He often worried be worry anout ,be worried about ,worry about ,worried about 为什么be worried about 前面要加be呢 而worry about就不要 worry about为什么会变成be worried about She is worried about her maths homework.在这句话中,为什么要用worry的过去形 there is nothing to worry about这句话后面为什么不能换成 to be worried? there is nothing to worry about这句话为什么后面不能用 to be worried abo He is ____(worry) about his father 什么时候用worry about 什么时候用be worried about