英语翻译 我们的课文 我不太明白 可以翻译一下？

once there was no money. if people wanted to get something, they had to give something. this is the way it used to be.
"i will give you my cow for your pig," a man would say.
"i'll give you my bowl if you give me a shirt," another would say.
"here are seven oranges for one fish."
"will you give me a chicken for a bag of corn?"
people had to trade thins every day. they had to give something to get something because there wasn't any money.
but they had to work out a good trade, one that came out even.
what could you get for two chickens? were there bags of apples a good trade for two bags of grapes? or one bag of apples for a little butter? what was an even trade? it was hard to know.
and it was too hard to carry around all the things for trading.people had to use too much time getting things they needed. so they thought of a new way to trade.
they thought of money.
money could &qu

（马克思政治经济学...）
当世上还没有货币的时候，如果人们想得到某些东西，他们必须给出一些东西，像这样：
一个人会说：“我用一头奶牛换你的一头猪。”
另一个人会说：“如果你给我一件衬衣，我就把我的碗给你。”
“给你七个橘子，换一条鱼。”
“我用一袋谷子换你一只鸡好吗？”
人们每天都必须交换物品。因为还没有货币，他们必须以物易物。
但他们必须找到一种公平交易的方式，使交易双方的价值对等。
两只鸡能换到什么？一袋苹果换两袋葡萄的交易公平么？如果是一袋苹果换一些乳酪呢？怎样算是一种公平交易？这很难回答。
而且，要通过物品交换得到所有东西太难了。人们不得不花费过多时间来取得他们所需的东西。因此，他们想出了一种交易的新方法——货币。
货币可以用来“代替”苹果，或者碗、猪等。而且一口袋钱要好过一麻袋猪。
有了货币，交易就不是那么难了。每个人都可以使用货币。想要一头猪的人可以用钱买到猪。卖出那头猪的人可以保存着那些钱，直到他自己需要些什么。人们可以为赚钱而工作，然后用工作所得的钱购买物品。
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but they had to work out a good trade, one that came out even.
work out
这里even是形容词，取对等、平等、同等、一致的意思，one that came out even中one是指前面的good trade，这句解释了什么叫a good trade。
work out简单说就是做出来，可以引申为设计出、计算出、作出等意思
所以整句话的直译意思就是：但他们不得不设计出一种“适宜的交易”，即能使（双方交换的）结果对等。
所以我直接就翻译成：但他们必须找到一种公平交易的方式，使交易双方的价值对等。

以前没有货币。如果人们想要得到某种东西，他们必须要给出某样东西。这是以前的方式。

“我用我的牛换你的猪。”一个人会这样说。
“如果你给我一件体恤我把我的碗给你。”另一个会说。
“七个桔子换一条鱼。”
“我给你一袋玉米，你会给我一只鸡么？”