She keep bothering me to help her like a child, how can I lie to her that I am busy?

I live with a relative and his wife keeps bothering me. I don't have a car so I can't go to library and pretend I am busy. I walk to work. I dont like school so I can't lie about I am going to return to school. yes she doesn't know my work schedule but I dont have a car to go anywhere. i am too embarrass to walk to work. The thing is I actually have stuff that I have to do and can't even finish it since she is always wasting my time.

She keep bothering me to help her like a child, how can I lie to her that I am busy?
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