Why is "came from" and not "come from"?

Several days ago, when I listened to "Words and Expressions", a programme in "Special English" by VOA.  I listened to a sentences like this. "It is surprising how many daily American expressions that Americans use every day came from the card game of poker".  Where the words "came from" is used in this sentence .In the beginning At first, I thought I listened heard "came from" wrongly and so I listened to the this sentence again and again repeatedly.,but it was Still it was, "came from".  ,then Only when I saw the text, it was "came from" that I indeed had heard correctly. So I don't know why is "came from" not "come from" here. My question now is why "came from" and not "come from"?

I would Much appreciated if anyone could can explain it!

By the way, I am learning English now and my English it is not good.  Please so you can correct this composition while you explaining the above question above.

Very simple, the actions happened in the past i.e. those terms were borrowed from poker. In your conclusion, I did not use the past tense is because the action stated at that time has not happened yet.

Your punctuation spacing is atrocious.  I assume as a student of English, that you didn't know the rules.  So here's the link to my article.  I sincerely do hoe that you learnt something that they don't teach in the class. 

http://www.italki.com/knowledge/page/Mechanics%20Of%20The%20English%20Language.htm