掷标枪技术性强，掌握它难度较大。

Javelin requires skill and is difficult to master.

youdao

我认为你最初低估了它的难度，对吧？

I think you underestimated how difficult it would be the first time, didn't you?

youdao

尽管这是个很重要的材料，但我认为它的难度太大，不适合我们的学生。

While this is very important material I think it's probably pitched at too high a level for our students.

《柯林斯英汉双解大词典》