Question

I shouldn't have been so rude to you句子可以改吗？

可以说成I shouldn't be so rude to you 吗？

Answer 1

每一种时态都是有意义的,不能随意改动。
i shouldn't have been so rude to you. 意思是：我之前对你非常粗鲁，我现在后悔了，现在觉得我当时不应该那么粗鲁。这个时态有道歉的意味。
i shouldn't be so rude to you. 意思是：我不应该对你这么粗鲁。这里的“so ”是一个程度，跟两个人都知道的某种粗鲁态度相比。比如，我粗鲁地对待了某个人，或者一个人对"you"很粗鲁，或者两个人观察到另一个人对另外一个人很粗鲁等等。这个有表态的意味。实际上，这种用法是非常少见的。

Answer 2

have been,说明是之前发生的事，be是现在的事。
意思分别是我之前不应该对你这么无礼
改完后为我不应该对你这么无礼。
但口语的话不用在意这么多。

Answer 3

It could be used like you indicate . but there is a have added in this sentence that could say the rude action happened ever in the past day, so you will not do the same thing to him. though ,you only use the be word which will not be figured out in past is meaning in the future that you will never do.
Hope you can see what I said.

Answer 4

每一种时态都是有意义的,不能随意改动。
i shouldn't have been so rude to you. 意思是：我之前对你非常粗鲁，我现在后悔了，现在觉得我当时不应该那么粗鲁。这个时态有道歉的意味。