题目

二力平衡的条件：作用在的两个力，如果大小，方向，并且作用在上，那么这两个力就相互平衡。 答案：【1】同一个物体上【2】相等【3】相反【4】同一条直线 Don't worry madam, your baby is looked after ________ here．The nurses are very ________． [　　] A．careful; carefully B．carefully; careful C．care; careless D．careless; care