They mean the same thing, but have slightly different tones to me. I don't like to start a sentence with "I want", it almost invites an "I don't care what you want" reply. Similarly switching to the imperative "Read the article on page 30" seems too domineering. I would always add a 'please' so as not to cause offense.Q1> When teachers have students do some activities, they might say "What I want you to do now is read the article on page 30 on your own" or "I want you to read the article on page 30 on your own."
This isn't so much awkward, as backwards. You want him to take his head off his desk. I would tell him to wake up or to pay attention.Q2> If you enter into your classroom to begin class, one of your student
is sleeping on his desk, how do you say to him?
If I say "Why do you have your head down? Put your head on your desk. Time for class!"
The difference, in my view, is the amount of care and attention given to the task. To jot down means to take rough notes, giving up precision for speed of writing. You have to write like this because people speak faster than you can write.Q3> When do you use "jot down"? It seems like there is no difference to
me between "jot down" and "write down" If different, could you give
me some examples to understand that?
They may say those. There are a lot of other ways of saying it too.Q4> When one studetn asks ohter student what class is going on, how
does he say?
What do we have this period? / What do we have this time? / What do
we have the first period?