Thank you Jack!

To make my dreams come true.

evergreen.

In this context the sentence should be " In some sects of Islam, Muslims are forbidden to eat THE FOOD that was paid by non-Muslims" . Article "THE" is used here in this sentence because of the addition of the clause " that was paid by non-Muslims" to it.

I can't stand cigarette smoke. It is so disgusting particularly in public places.

In the context you mention above "after" isn't used. If you ate an apple an hour ago, you can say " It's an hour since I ate an apple" and "It's an hour since I had breakfast."

For Vietnamese learners it is because of two things; their phonetic organ and  Vietnamese itself. In Vietnamese the consonant  at the end of a word is never pronounced.  Therefore people don't have the habit of pronouncing it. On the other hand, the phonetic organ of the Vietnamese is naturally formed to pronounce Vietnamese words itself, so it is usually very difficult for Vietnamese speakers to pronounce it. So is the S at the end of a plural word in English.  Vietnamese people have to work hard on pronunciation when learning English..