Proszę o pomoc. Język angielski

GRAMMAR 3 Correct the mistakes in the sentences. 1 The house where stands at the top of the hill belongs to my relatives.
2 The little boy hurt itself.
3 They've been rivals ever since they first played against themselves.
4 A child which siblings are younger is usually very responsible.
5 This is a great game, I'm sure we'll enjoy ourself.​