Помогите решить English Language Complete the sentences Present Perfect Continius/ Present Continius

1. Sam has become stronger since he came to the gym last year.
2. John has been reading a newspaper since early morning.
3. The students are still writing the test.
4. I have been counting sheep for the last ten minutes.
5. How long have you been waitig for?
6. The child is dirty because she has been playing with sand.
7. What is going on at the moment?