They leant later that Chief Naga had been educated at Oxford University some years before.
问题描述：
They leant later that Chief Naga had been educated at Oxford University some years before.
为什么要用leart和had been educated?
答
这是一般过去时和过去完成时.they learnt(他们了解到)这一动作发生在过去,所以用一般过去时,而Chief Naga受教育这一动作则发生在“they learnt(他们了解到)”这一动作之前,即发生在过去的过去,所以用过去完成时,并且...