48. 主语＋be动词＋形容词＋动词不定式
The article is easy to understand. 这篇文章很容易理解。
The story is interesting to read. 这个故事读起来很有趣。
49. It is＋形容词＋that从句
It是形式主语，that从句才是真正的主语。如：
It is wrong that we look down on disabled people.
看不起残疾人是错误的。
It is important that you have your own support team.
有自己的支持团队是非常重要的。
50. It is＋形容词/a good idea＋动词不定式
It is useful to have support teams.
有支持团队是非常有用的。
It is necessary to learn English well.
学好英语是非常必要的。
51. It is＋形容词＋for sb.＋动词不定式
对他们来说记住这么多单词是很难的。
It is very difficult for them to remember so many words.
对学生们来说，做眼保健操是十分必要的。
It's quite necessary for students to do the eye exercises.
(1) It's good/better/best/bad/worse/worst (for sb.) to do
做某事 好/更好/最好/糟糕 (很不好)/更糟糕/最糟糕
晚饭后散步是很好的。
It's good to take a walk/go for a walk after dinner/supper.
对他们来说坐飞机去三亚更好。
It's better for them to take an airplane to Sanya/to fly to Sanya.
在强烈的阳光下看书很不好。
It's very bad to read in strong sun.
(2) It's good/bad for ... 对……有好处/不好。
练习游泳对你的肺部有好处。
It's good for your lungs to practice swimming.
(Practicing swimming is good for your lungs.)
52.A＋be＋方位＋of＋B A在B的某个方位
His house is south of mine. 他的房子在我房子的南面。