"What took you so late Andrew ? If you had been seen by a student of my school , then it would have be very difficult for me to repair you. Take down all of the people who are an obstacle for me. That  is your  job  . Your ultimate task , Andrew.
correct it

Dear student 

The answer is - 

What took you so long Andrew ? (What took you so late is incorrect. You either say, “why are you so late?” or “what took you so long?”)

If you had been seen by a student of my school, then it would have been very difficult for me to repair you.

Take down all of the people who are an obstacle for me. That is your job, your ultimate task Andrew.
 

Regards