Take another look at the sentence:

When Minori left Japan to study in the United States, she thought that she would miss her mother's delicious home cooking, however, after her first taste of a bacon cheeseburger, she didn't care if she ever returned to Japan.

She didn't care is a main clause. If she ever returned to Japan is a subordinate clause. A subordinate clause is an incomplete thought which you must attach to a main clause. When a subordinate clause follows a main clause, you generally need no punctuation between the two.

Go back to the sentence to try again.

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