I haven't been back to the island是什么时态?为什吗要用been?

in I haven't been back in ages. I haven't been back to the island是什么时态?为什吗要用been? have .since did区别have .since have done?eg：I haven’t seen you since I’ve been back.I haven’t seen you since I was back. 翻译I haven't been there I haven't been to the mountains I haven't been three for five years 翻译I haven't been to shenzhen yet any place I haven't been to 的意思 No,I haven't been to Ocean Park yet? You haven't been when I exist神马意思 i haven't been around.我翻的不对 having been back for a month,i haven't even got around to unpacking yet这个even什么意思,不是有yet了吗 my parents haven't been to shanghai,and i haven't been to shanghai _____.either还是neither?为什么? I haven't been able to be outdoors for so long haven't been 为什么要用 —Haven't seen you for ages.Where have you been?-I_____ to New York City.I just got back.A.was sent B.have been sent C.had been sending D.would be sent I never been there before=I haven't been there before? I never been there before=I haven't been there before? i’ ve never been to abroad. 和i haven't ever been to abroad. 一样吗