Question

we must repay our parents by taking good care of them(change into compound)​

Answer 1

We must take care of our parents and repay them

Answer 2

Answer:

we must take care of our parents so that we can repay them.

Explanation:

the 'and' one might be correct

but what I think is that here

the sentence has two clauses one tells the action and other tells the purpose for it

so using 'so that' might be better option