中文：

融资融券交易又称“证券信用交易”，是指投资者向具有融资融券业务资格的证券公司提供担保物，借入资金买入证券（融资交易）或借入证券并卖出（融券交易）的行为。

简单说就是，投资者需要先向证券公司提交担保物，然后借入资金购买股票或借入股票进行卖出。这种交易方式可以在一定程度上放大投资者的交易规模，提高交易的灵活性，但同时也增加了投资者的风险。

融资融券交易分为融资交易和融券交易两种。融资交易是指投资者以自有资金或证券作为质押，向证券公司借入资金用于购买股票；融券交易则是投资者以自有资金或证券作为质押，向证券公司借入股票用于卖出。

融资融券交易在一定程度上可以促进市场的活跃程度，提高市场的交易量，同时也是一种高风险的投资方式。投资者在进行融资融券交易时需要充分了解风险，合理控制杠杆比例，做好资金管理和风险管理。

英文：

Margin trading and short selling are also known as "security credit trading", which means investors use securities as collateral to borrow funds from a brokerage firm to buy securities (margin trading) or to sell securities (short selling).

In simple terms, investors need to submit collateral to the brokerage firm before they can borrow funds to buy stocks or borrow stocks to sell. This trading method can amplify investors' trading scale and improve flexibility in a certain extent, but it also increases investors' risks.

Margin trading and short selling are divided into two types: margin trading and short selling. Margin trading means that investors use their own funds or securities as collateral to borrow funds from brokerage firms to buy stocks; short selling means that investors use their own funds or securities as collateral to borrow stocks from brokerage firms to sell.

Margin trading and short selling can promote market activity and increase market trading volume in a certain extent, and are also high-risk investment methods. Investors need to fully understand the risks when conducting margin trading and short selling, reasonably control leverage ratio, and do a good job in capital management and risk management.