中文：

开放式基金是一种常见的投资工具，它允许投资者在基金的存续期内申购和赎回基金份额。与封闭式基金不同，开放式基金的发行规模不是固定的，而是可以随时增加或减少。

开放式基金通常由基金管理公司发行和管理，其投资目标可以是股票、债券、货币市场工具或其他类型的资产。投资者可以通过银行、证券公司或其他代销机构购买或赎回开放式基金的份额。

开放式基金的主要特点包括：一是基金的份额是可变的，投资者可以根据市场情况和自身需求随时申购或赎回基金份额；二是基金的价格由基金的净资产值和供求关系决定，与市场波动密切相关；三是基金的投资策略相对灵活，可以根据市场变化和投资目标进行调整。

开放式基金的投资策略主要包括长期投资、短期投资、指数化投资等。长期投资策略旨在追求长期收益，通常投资于股票和债券等资产；短期投资策略则注重短期收益，可能涉及货币市场工具、回购等；指数化投资策略则是通过跟踪某个指数来获取相应的收益。

总的来说，开放式基金是一种灵活的投资工具，投资者可以根据自己的风险偏好和投资目标选择适合自己的基金进行投资。

英文：

Open-end funds are a common investment vehicle that allows investors to purchase and redeem fund shares during the fund's duration. Unlike closed-end funds, the issue size of open-end funds is not fixed and can be increased or decreased at any time.

Open-end funds are typically issued and managed by fund management companies and can invest in stocks, bonds, money market instruments, or other types of assets. Investors can buy or redeem shares of open-end funds through banks, securities companies, or other distribution channels.

The main features of open-end funds include: first, the fund's shares are variable, and investors can purchase or redeem shares at any time based on market conditions and their own needs; second, the price of the fund is determined by the net asset value and supply and demand, and is closely related to market fluctuations; third, the investment strategy of the fund is relatively flexible and can be adjusted based on market changes and investment objectives.

The investment strategies of open-end funds mainly include long-term investment, short-term investment, indexing investment, etc. Long-term investment strategies aim to pursue long-term returns and typically invest in assets such as stocks and bonds; short-term investment strategies focus on short-term returns and may involve money market instruments, repurchase agreements, etc.; indexing investment strategies are to obtain returns by tracking a certain index.

Overall, open-end funds are a flexible investment tool for investors to choose a fund that suits their risk preferences and investment objectives.