屏南白水洋鸳鸯溪:请问have collected 和have been collecting 有什么区别

请问have collected 和have been collecting 有什么区别 How long have you been collecting shells？与How long have you collected shells?的区别 How long have you been collecting shells？与How long have you collected shells?的区别 wallace stevens的诗集hermonium 1923和collected poems 请问have been和have gone的区别 请问HA阳性要紧吗？ 请问have sb. do sth.和have sth. done分别是什么意思呢？？ 请问shouldn't have done和might not have done 在此题中的区别？ have school和 have class的区别 have school和 have class的区别