understand的过去式和过去分词和现在分词
understand的现在分词 understanding；过去式 understood；过去分词 understood；
understandv.懂；理解；领会；了解
We need a clear understanding of the problems involved.
我们需要了解清楚所涉及的各种问题。
This research has done much to advance our understanding of language learning.
这项研究大大提高了我们对语言学习的认识。
He\'s too young to understand the ways of the world.