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I'm confused which one is correct. I hear #1 and #3.
1) The bottom of my feet are sore.
2) The bottom of my feet is sore.
3) The bottoms of my feet are sore.
4) Bottoms of my feet are sore.
I thought #3 was correct, but I found a grammar book saying, “Certain expressions with of are an important exception to the rule about prepositional phrases. Some of the wine…, most of the lesson… All of the material… These sentences discuss a part of something (or even all of it), so the subject-verb agreement depends on whether the word after of is singular or plural. Some of the wine is spoiled. Some of the apples are spoiled.” If we consider “the bottom” as a part of foot, should we apply this rule and say #1?
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# 3 is best - but soles is more apt than bottoms!
Comments  
Wouldn't it be the soles of my feet? Not to be confused with souls. Lol.
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Some Americans told me that they use "bottom" more than "sole". Isn't that true?
I think the structure 'some of something is/are ...' falls in the countable/uncountable rule.
- Some of the wine is spoiled. (singular, for wine is uncountable)
- Some of the apples are spoiled. (plural, for apple is countable)
- Some of the wine bottles are broken. (countable)

I think only #3 is correct.
- The bottoms of my feet are sore.
- The bottom of my left foot is sore.
 suzi's reply was promoted to an answer.
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