4) Reflecting in my writing performance

In one of our class we learned about tag questions, another unusual form to write in English, but important to know and use sometimes. Most common we use that when we talk with someone, like with friends or family. 

We use tags in spoken English but not in formal written English. They are not really questions but are a way of asking the other person to make a comment and so keep the conversation open. Making a tag is very mechanical. To make a tag, use the first auxiliary. If there is no auxiliary, use do, does or did. With a positive sentence, make a negative tag and with a negative sentence, make a positive tag.

Examples of tag questions;

• It's beautiful, isn't it?
• He has been, hasn't he?
• You can, can't you?
• It must be, mustn't it?
• You know him, don’t you?
• He finished it, didn't he?
• He will come, won't he?

Video to explain better this topic. 

Bibliography
http://www.englishgrammarsecrets.com/questionstags/menu.php