中文：

利息是指借款人向出借人支付的报酬或收益。简单来说，就是借款人使用出借人资金所需要支付的费用。利息是金融市场中的重要组成部分，它反映了资金的价格，也是投资者进行投资决策的重要参考指标。

利息的计算方法通常是根据借款金额、借款期限和利率来确定的。利息可以分为年利息、季度利息、月利息等，根据借款期限和利率的不同而有所区别。在签订借款合同时，双方会约定借款利率和利息支付方式等事项。

利息的作用有很多种。首先，利息是借款人使用出借人资金所需要支付的费用，它可以平衡出借人和借款人之间的利益关系。其次，利息是投资者进行投资决策的重要参考指标，它可以反映资金的风险水平和市场投资环境。此外，利息还可以作为经济杠杆来调节市场供求关系和资源配置。

英文：

Interest refers to the compensation or yield paid by a borrower to a lender. In simple terms, it is the fee that borrowers need to pay for using the lender's funds. Interest is a crucial component of the financial market, reflecting the price of funds and serving as an important reference indicator for investors to make investment decisions.

The calculation method of interest is usually determined by the loan amount, loan period, and interest rate. Interest can be divided into annual interest, quarterly interest, monthly interest, etc., which differ according to the loan period and interest rate. When signing a loan contract, both parties will agree on the interest rate and the payment method of interest.

Interest plays many roles. Firstly, interest is the fee that borrowers need to pay for using the lender's funds, which can balance the interests between borrowers and lenders. Secondly, interest is an important reference indicator for investors to make investment decisions, reflecting the risk level of funds and the market investment environment. In addition, interest can also serve as an economic lever to adjust market supply and demand and resource allocation.