中文：

央行发行国债卷是货币政策的重要工具之一，也是国家财政政策的重要组成部分。国债卷的发行时间和发行量通常是由国家财政部和央行根据宏观经济形势和政策需要共同决定的。

一般来说，央行会在季度末或年末发行国债卷，以实现货币政策的调控和财政政策的配合。在市场经济的条件下，央行发行国债卷还可以促进资本市场的发展和规范化，提高金融市场的效率和稳定性。

具体来说，央行发行国债卷的方式有多种，包括定向发行、公开招标、承销包销等。其中，定向发行主要面向特定投资者，如商业银行、保险公司等；公开招标则面向全体投资者，通过竞价方式确定发行价格；承销包销则是通过承销商或包销商向投资者销售国债卷。

在投资领域，央行发行国债卷也是一项重要的投资品种。国债卷具有信用等级高、风险低、流动性好等特点，是投资者进行稳健投资的首选之一。对于个人投资者而言，购买国债卷可以获得固定的利息收益，同时也可以享受国家经济发展的红利。

总的来说，央行发行国债卷是一项重要的经济活动，对于国家宏观调控和金融市场的发展都具有重要意义。

英文：

The issuance of government bonds by the central bank is one of the important monetary policy tools and an important component of national fiscal policy. The time and amount of issuance of government bonds are usually jointly decided by the Ministry of Finance and the central bank based on the macroeconomic situation and policy needs.

Generally speaking, the central bank will issue government bonds at the end of each quarter or year to achieve monetary policy regulation and fiscal policy coordination. Under market economy conditions, the issuance of government bonds by the central bank can also promote the development and standardization of capital markets, improve the efficiency and stability of financial markets.

Specifically, there are various ways for the central bank to issue government bonds, including targeted issuance, public bidding, underwriting and syndication. Among them, targeted issuance is mainly targeted at specific investors such as commercial banks, insurance companies, etc.; public bidding is open to all investors, and the issue price is determined through competitive bidding; underwriting and syndication are sold to investors through underwriters or placement agents.

In the investment field, the issuance of government bonds by the central bank is also an important investment variety. Government bonds have high credit rating, low risk and good liquidity, making them one of the preferred choices for investors to make stable investments. For individual investors, purchasing government bonds can obtain fixed interest income while also enjoying the dividends of national economic development.

Overall, the issuance of government bonds by the central bank is an important economic activity that has great significance for national macroeconomic regulation and the development of financial markets.