It also leads to the specialization of labor, which in turn leads to trade.

它还导致劳动力的专业化，进而导致贸易。

You would think that larger size, theoretically, creates more specialization of labor, and ultimately higher productivity.

你可能会认为，从理论上讲，更大的规模会创造出更专业的劳动力，并最终带来更高的生产率。

Advantage: Especially if you grow grain, you can create a food surplus, which makes cities possible and also the specialization of labor.

优势：特别是如果你种粮食，你可以创造食物盈余，这使得城市成为可能，也使劳动力专业化。