英语咋说：你难忘记流浪的岁月， 挥挥手只留下背影

It's difficult for you to forget the time of vagancy,yet still wave your hands leaving only the shadow.

You can hardly forget the days that you were away from home.

You shook your hands and found that there's only shadow leaving.

你难忘记流浪的岁月，
You have forgotten the days when you were wandering (roaming)

挥挥手只留下背影
and you waved and parted leaving your back behind

You difficult to forget roams about the years, wave the hand only leave behind back