These behaviours can be observed among many children who have lost a parent or other loved one.这类行为可能出现在失去了父母或亲人的儿童身上。At birth, an infant can perform only simple reflex actions and behaviours.刚出生的婴儿只会做出简单的反射动作和行为。Communication involves a variety of behaviours which are difficult to categorise.沟通涉及多种行为，很难归类。