Here is the translation:

交易是指在证券市场中根据市场价格调整投资组合的过程。交易的目的是为了实现投资的目标，包括获取投资回报、避免投资风险和提高投资回报率。

(Translation: Trading refers to the process of adjusting investment portfolios according to market prices in the securities market. The goal of trading is to achieve investment objectives, including generating investment returns, avoiding investment risks, and improving investment returns.)