Study this example situation:
- Susan comes from Indonesia. Now she is in London to continue her studies. Besides she studies at one of the colleges in the city at the day time, she also works part-time at a hotel at night. She is still young but she doesn't live on her parents. She works hard night and day. However, she isn't working tonight because she isn't feeling very well. According to her doctor, he is getting sick because of hard work.
The form of the simple present tense
The agreement pattern between the subject and the predicate of be functioning as a full verb in the simple present tense: 'I am / he is / they are / etc. + subjective complement; and apart from the full verb of be, the agreement: I / you / we / they come / she comes / he studies / she misses ... / he watches ... / she has ... / etc.
We use the simple present tense to say that something happens repeatedly or permanently. It is not important whether the action is happening at the time of speaking.