> since it starts with "who"
OK :). At least my commata were right. Can you sum up on a few lines where a comma is due? No prob if some exotic thing is missing. Just write what you think a foreigner must at least get right.
Can you also say something to my "an hour"/"a hour" question, please?
Use "an." This is because the h in "hour" is silent, so it is acting as a vowel, i.e. an apple, an editor, an item, an owl, an umbrella.