【中文版】

利息是指借款人按照借款合同的规定，向出借人支付的报酬。它是货币的时间价值体现，也是资金使用者支付给资金所有者的报酬。

利息的计算方式通常包括年利率、月利率和日利率。年利率是以年为单位计算的利率，通常以百分数表示；月利率是以月为单位计算的利率，通常以千分数表示；日利率是以日为单位计算的利率，通常以万分数表示。

利息的作用是多方面的。首先，利息是衡量资金时间价值的尺度，可以帮助人们比较不同时间点的资金价值。其次，利息可以作为投资项目可行性分析的重要指标之一，帮助人们评估不同投资项目的收益和风险。此外，利息还具有调节经济活动的作用，通过调整利率水平来影响投资和消费行为。

在日常生活中，利息的例子有很多。比如，我们在银行储蓄存款时会获得一定的利息收益，贷款时需要支付一定的利息费用，购买债券时会获得债券利息等。

总之，利息是货币的时间价值体现，是借款人向出借人支付的报酬，也是资金使用者支付给资金所有者的报酬。它是经济活动中不可或缺的一部分，具有多方面的作用。

【英文版】

Interest refers to the payment made by the borrower to the lender in accordance with the provisions of the loan contract. It is the time value of money and the compensation paid by the user of funds to the owner of funds.

The calculation methods of interest usually include annual interest rate, monthly interest rate and daily interest rate. The annual interest rate is calculated based on the unit of year and usually expressed in percentage; the monthly interest rate is calculated based on the unit of month and usually expressed in per thousand; the daily interest rate is calculated based on the unit of day and usually expressed in per ten thousand.

The function of interest is multiple. Firstly, interest is the measure of the time value of money, which can help people compare the value of funds at different times. Secondly, interest can be used as an important indicator for investment project feasibility analysis, helping people evaluate the收益and risks of different investment projects. In addition, interest also plays a role in regulating economic activities by adjusting the level of interest rates to affect investment and consumption behavior.

There are many examples of interest in daily life. For example, we will obtain a certain interest income when we deposit money in the bank, we need to pay a certain interest fee when we apply for a loan, and we will obtain bond interest when we buy bonds.

In summary, interest is the time value of money and the compensation paid by the borrower to the lender. It is an indispensable part of economic activities and has multiple functions.