.......The subject of the sentence misplaced.......

！Don't say: Last week visited our school a man.

√  Say: A man visited our school last week.

..........The subject misplaced in questions.......

！Don't say: You were at the cinema yesterday? They'll come with us tomorrow?

√  Say: Were you at the cinema yesterday? Will they come with us tomorrow?

..........The subject misplaced in questions beginning with an interrogative word.......

！Don't say: Why you were absent last Friday?

√  Say: Why were you absent last Friday?