题目

Why should I teach my children history? That sounds like a stupid question to even ask. But, as I hear different home schooling teachers discuss history, I get the idea that there may be different reasons for teaching history. Let me briefly explain the three good reasons for studying history and two bad reasons for studying history. The major reason I see for studying history is that we can learn from the past. I am convinced that the world would be a much better place if more people understood the successes and failures of the past and the things that made these successes and failures. Howev一个三肽化合物中，一定含有 [     ]A．三个肽键 　B．三个肽链 　C．三个氨基 　D．以上都错