There’s no need to worry about your father.（改为同义句） You _____ _______ to worry about.

There’s no need to worry about your father.（改为同义句） You _____ _______ to worry about.

don't need

don't need 本句中need是实意动词，要借助于助动词do来构成否定句

You don't need to worry about your father.
把Need作为实义动词。后面就能用不定式了