what a pity!You must have enjoyed yourselves very much.But the school had never had such a young helper.请解析
问题描述：
what a pity!
You must have enjoyed yourselves very much.
But the school had never had such a young helper.
请解析
答
解析：What a pity!!多么遗憾啊
have enjoyed yourselves 到现在为止你过的很愉快吧
had never had such a young helper从以前到现在从来没有过这么年轻的助教的先例。
答
你一定玩得很高兴.
但是这学校从来没有这样的年轻助手.
楼上说得很好，不过must have done表示的是对过去的一种很有把握的推测，翻译的时候作 一定，想必 解。
答
你想必对自己很欣赏,
但我校从来没招过如此年轻的助手.
答
你们一定玩的很愉快。
但是我们学校从来没有一个如此年轻的助手
答
你必须玩得高兴.
但是这学校从来没有这样的年轻助手.
enjoy oneself 某人玩得高兴=have a good time
had had sth.过去完成时态,这句话表示过去某一时间之前拥有某物