1. The homework is very difficult to finish.

（作业完成起来非常困难。）

2. It's difficult to learn a new language.

（学习一门新语言很困难。）

3. The problem is difficult to solve.

（这个问题很难解决。）

4. It's difficult to understand his jokes.

（很难理解他的笑话。）

5. The mountain is difficult to climb.

（爬山很困难。）

6. It's difficult to keep up with the fast pace.

（跟上快节奏很困难。）

7. The task is difficult to complete on time.

（按时完成任务很困难。）

8. It's difficult to find the right words.

（很难找到合适的词语。）

9. The project is difficult to manage.

（管理这个项目很困难。）

10. It's difficult to remember all the details.

（很难记住所有细节。）

补充说明：

该结构中，"it"作形式主语，真正的主语是后面的不定式短语"to do sth"。- 该句型可替换形容词作表语，例如：

The movie was very difficult to watch.

（这部电影非常难看。）

通过以上示例，可以灵活运用该结构表达不同场景下的困难感受。