关于英语单词find用法的一个句子, Old people may find it a little difficult climbing up and down the steps,but it is still much safer than walking across the road with all the moving traffic. 这是我在一本英语书上看到的句子,感觉有点问题. 此句中的climbing为什么不是to climb,我记得是“find it adj.to do sth.” 但这里为什么是climbing?