According to the position of the subject in Turkish, there are the above two expressions: in the first form, although the formal subject "you" is omitted, the suffix -sin is attached at the end of the sentence to express the subject "you"; The second form is the complete form. But I prefer to communicate in the first form. Of course, there is nothing wrong with writing in the third form, Sen bir asker. (note Bir asker. It means "you are a soldier" instead of "you are a soldier", because the subject "you" does not appear anywhere. )