① It is a crime to defy the law.

② He is rich; he does not know what it is like to be poor.

③ It is common in a large city, for families that have lived for years in the same building not to know one another by name.

④ It would be all wrong for a scientist to get emotional when he describes a daffodil; and it would be all wrong for a poet not to.

⑤ It is no use trying to persuade him.

⑥ It is no use your trying to deny the fact.

⑦ It is no good politicians talking like that.

⑧ It is curious situation that the sea, from which life first arose, should now be threatened by the activities of one form of that life.

⑨ It is worth while visiting South Sea Islands.=South Sea Islands are worth visiting.

⑩ In order to master the English language, it is necessary to understand the structure of the English sentence.