“apart from”，“except”，“other than ”，“besides”
are “apart from”，“except”，“other than” ，“besides” interchangeable？
If they are not，then whats the difference among them？i have seen something about their definitions from books，but i also have met lots of sentences in which they are used differently from what i have seen about their definitions。
for example，in books ，apart from is mainly used in negative cases ，like “Apart from clothes and bedding, I have nothing.

”，which means i have nothing but clothes and......
but in lots of affirmative sentences，you can also see the “apart from” used，like“Apart from peppers and aubergines, many other vegetables grill well.”
my god...how can they be confusing like that？

Question

“apart from”，“except”，“other than ”，“besides”
are “apart from”，“except”，“other than” ，“besides” interchangeable？
If they are not，then whats the difference among them？i have seen something about their definitions from books，but i also have met lots of sentences in which they are used  differently from what i have seen about their definitions。
for example，in books ，apart from is mainly  used in negative cases ，like “Apart from clothes and bedding, I have nothing.

”，which means i have nothing but clothes and......
but in lots of affirmative sentences，you can also see the “apart from” used，like“Apart from peppers and aubergines, many other vegetables grill well.”
my god...how can they be confusing like that？

Answer

Apart from means both "except for," and "as well as," which is why it is correct in both of the sentences that you have cited.  "Other than," and "besides," can also have the same two meanings.

"Except," stands apart from the other three items because it cannot be used to mean "as well as."

Answer

They are not interchangeable. What meaning they produce depends on the relations they form with other word phrases in a sentence. When learning, you should focus on how YOU will use the language to procude meaning in a clear way. You do not need to learn all the ways to say something, but you do need to be able to interpret the many ways that different people express themselves (as long as they are making sense, and using the langauge in an acceptable way).  This is called an idiolect and everyone has one. The idiolect is the way an individual uses the langauge and everyone does it differently. Your goal should be to develop your own style (idiolect)  of using the langauge. As you progress, you will naturally begin to discover different ways to say things.

Answer

The "rules" that you see on pages like this
https://www.crownacademyenglish.com/besides-except-apart-from/
are patterns and suggestions, not real rules.  Natives will break the "rules" all the time, but if they are writing something important, they might prefer one word instead of the other.
 
"I like all animals except hamsters" and "I like all animals besides hamsters" are both fine (at least to my American ears), but the version with "except" feels a little bit better.

There IS one rule on that page that I agree with: if you mean "in addition to",  it's best to say "in addition to"", but "besides" and "apart from" are both OK.  "Other than" is a bit weird, but acceptable. However, "except" is WRONG. 
Best choice: In addition to my cat, I also have two dogs
OK: Besides my cat, I also have two dogs;  Apart from my cat, I also have two dogs. 
Weird but acceptable: Other than my cat, I also have two dogs.
WRONG: Except (for) my cat, I also have two dogs.

Also, there is a slight difference in formality.
As I see it
Somewhat formal---> somewhat casual
Apart from-->other than-->except-->beside(s)