Hi Stephen, both 次 and 遍 can be used to describe the times an action happened, but there are still some differences between them. Using 次 more emphasizes that how many times the action happened. Such as 我去过两次北京。 and 给他送了两次礼物。 While 遍 emphasizes the whole action from the beginning to the end. Such as 这首歌我听了两遍。 and 我看了两遍这部电影。 Generally speaking, 次 lays the emphasis on the occurrence of an action as a whole event while 遍 on the process and thorough execution of an action. HTH.

Not big difference, More common some"次"；"遍”more rigorous and it can be used oral English，"次" can be used in written and spoken English. For example:1.一日三次，一次一片（drug）2.这本书我看了三遍（May be finished every time）.这本书我看了三次（Might not be finished every time）

"遍" is more formal and literary. :)

遍 is you do something and it lasts sometime. (implies do something from the begining to the end) So it's usually related to words/languages/ articles/ movies etc 我读了一遍这篇文章。 I read this article( from the begining to the end) 我看了一遍这部电影。I watched this movie (from the beging to the end) 我听了一遍这首歌。I listened this song (from the begining to the end) 次 is about how many time one thing happened 我读过一次这篇文章。 I have read this ariticle once. 我看过一次这不电影。I have watched this movie once. 我听过一次这首歌。 I have heard this song once. you may have noticed the sentences I used, you can use both of 次 和遍 。But emphasis on different things. Usually the sentences that you can use 遍， you can always use 次。 And sometimes you shouldn't use 遍。 每个人有三次机会。 Eveyone has three chances. (RIGHT) 每个人有三遍机会。（WRONG)

不知道你能不能看懂全部的中文。 遍 一般情况下我们说是完整的看过，这本书我看过一遍，是说从开始到最后。 这本书我看过一次。可能是说我看了一次，但是没看完。