Through, rough and cough.

English has so many exceptions to rules of pronunciation that we tend to make up new ones where none are warranted, especially with foreign words.

I have actually heard people pronounce "Iran" as eye-RAN, where "ran" sounds like the past tense of "run". These are generally the same people who pronounce "Iraq" as eye-RACK.

When I was a little girl, I pronounced Socrates as SO-krates (2 syllables). When I was corrected ("SOCK-rah-teez, honey.") I applied the lesson to Descartes. DESS-kar-teez. I was very proud of myself.

Foreign words don't come with a handbook. We only learn how to pronounce them through familiarity. We became familiar with Iran when our embassy in Tehran was taken over. We've become more familiar with Iraq recently too.