如果你不知道文章的意思，光背诵它是没有用的。

It's no use reciting a composition if you don't know its meaning.

youdao

当社会需要重建时，试图依照旧的计划重建它是没有用的。

When society requires to be rebuilt, there is no use attempting to rebuild it on the old plan.

youdao

但是如果你的确是没有用它做任何事情，它只不过是看不见的，因此，它是-，做的好，第二号的同学。

But if you don't actually do anything with it, — it simply disappears, and, therefore, it's — well done, classmate Number Two.

youdao

But if you don't actually do anything with it, -- it simply disappears, and, therefore, it's -- well done, classmate Number Two.

但是如果你的确是没有用它做任何事情，它只不过是看不见的，因此，它是-,做的好，第二号的同学。

哈佛公开课 - 计算机科学课程节选