A three-year-old might need help in understanding that other children feel pain just as he does, and that hitting a playmate over the head with a heavy toy requires an apology.

一个三岁的孩子可能需要他人帮助，才能理解其他孩子也和他一样感到疼痛，用沉重的玩具打了玩伴的头后需要道歉。