它们难以使用，还占用了图书馆很大的空间。

They were difficult to use and took a lot of space in a library.

youdao

1994年，互联网发展缓慢，难以使用，所以没有人能通过互联网挣钱。

In 1994, nobody was making any real money from the Internet which was still very slow and hard to use.

youdao

这些系统往往非常庞大，难以使用。

Those systems are usually bulky and difficult to use.

youdao

A little indirect but not so indirect that is difficult to understand. You should use this often.

有一点委婉，但不至于委婉到让人难以理解。应当尽量多使用这种句型。

Why don't 课堂 - SpeakingMax英语口语达人

And we could not preserve the quality of human life

如果不使用动物做实验，我们就难以保持人类的生活质量，

需要动物实验吗？ - SpeakingMax英语口语达人