If a lawyer is a lack of education, history, law. A lawyer will not be able to know the source of the legal system, and will not be able to have a basic knowledge as much as it should.
If the law is absent, the study of legal history. Lawyers can not know the source of each legal system and may not have as much knowledge as they could be.
If the lawyer will lack the history law. The lawyers will not know where to go to law of each system and will not be able to have basic knowledge as much as.