We're a small team here offering a free service and we have to deal with a lot of comments from users every day. I don't want to suggest that you shouldn't ask questions but do please try to keep them short and directly relevant to the material on the page. To answer this properly we'd need to write a comment longer than the material on the page, I suspect! However, here you've asked four different grammar questions which each require quite detailed explanations.
As we're teachers and we want to help learners we try to answer other questions too, including more general questions about the language. The comments section is primarily for providing explanations relating to the tasks on the page or the explanations/information on the page. We appreciate your keenness to learn but this isn't the kind of question we can answer in the comments section, I'm afraid. He wonders what is happening … Book traversal links for Present continuous One day when he is playing Quidditch he sees a strange object in the sky. Harry Potter is a pupil at Hogwarts school. Well, he 's carrying a big stick and he looks a bit dangerous, so I 'm wondering what to do … The other day I 'm just walking down the street when suddenly this man comes up to me and asks me to lend him some money. We can use the present continuous to talk about the past when we are: Note that we normally use always with this use. something which happens again and again:.something which is changing, growing or developing:.What sort of music are they listening to? What sort of clothes are teenagers wearing nowadays?
These days most people are using email instead of writing letters.