"I enjoy going shopping alone."
自己 means myself 我一个人 also means myself. so 我自己一个人 means by myself myself....and that's correct is it???
This is one of three possible correct answers. 自己 and 一个人 should both be accepted as correct answers.
all three are correct I believe. At least I have heard chinese people say all three.
Yes. 自己 just has a strengthening effect here: "alone and by myself". Just 一个人 is also perfectly fine, though.
Half these questions require one, the other or both. No explanation of the rules
There are no rules for things like this. There are just various ways of saying the same thing. Different people use different speech habits.
In "arranging words", DL tries to CHEAT us by separating characters with strange ways. Be careful!
you don't need 自己 and 一個人 together so saying “我喜歡自己去買東西” should be accepted