Which is your sister's favourite days?的同义句._______ _______ _______ your sister _______ ______

Which is your sister's favourite days?的同义句._______ _______ _______ your sister _______ ______
Which is your sister's favourite days?的同义句._______ _______ _______ your sister _______ ______

Which is your sister's favourite days?的同义句._______ _______ _______ your sister _______ ______
What days does like best

___Which____ ____day___ __does_____ your sister ___like____ __best____？

what day is ;most like

（Which day does）your sister（like best）?
或者（Which days does）your sister（like best）?
你的第一句话有问题，应该是favourite day，不是days；或者把is改为are