下列哪种方法不属于间接式学校健康教育方法（）。
A.讲座
B.广播
C.卫生科教电影
D.网络系统性学习
E.卫生知识图片展览
参考答案：A
He worked hard and achieved what he set out to do, but ________ what he had owned, including his health and his marriage.
A．at the mercy of
B．at the risk of
C．at the cost of
D．at the service of
聚酰胺树脂中含有下列哪种结构？（）
A.
B.
C.
D.
