SAT IE题目提问~?

问题描述:

SAT IE题目提问~?
Chess players find that playing against a computer is helpful to improve(A) their(B) skills, even though(C) no chess-playing computer has yet won(D) a championship. No error (E)
我还是不懂为什么不可以是is helpful to improve. 哪儿错了啊!?

因为是be helpful to sth,而不是to do sth.可是字典上的例句感觉也是be helpful to do啊。比如说It can be helpful to think of leadership growing in a series of transitions in self-awareness, skill, and responsibility.  考虑一下领导力在自我认知、责任感以及技巧方面的一系列转换是很有帮助的。It would be helpful to analyze what search phrases are bringing people to your site.  它有助于帮助你分析是什么搜索短语把人们带到了你的网站。注意这些例句中的主语it都是形式主语 语法需要加强