Q: What is the organizational structure of the United Nations?

The United Nations is composed of the following bodies:
　　General Assembly（大会）
　　Security Council（安全理事会）
　　Economic and Social Council（经济及社会理事会）
　　Trusteeship Council （托管理事会）
　　International Court of Justice（国际法院）
　　Secretariat （秘书处）

The General Assembly is held once a year (from the third Tuesday of September) to discuss general U.N. functions. Advice is then given to the Security Council based on these discussions. If necessary, an extraordinary general assembly is held.

The Security Council has direct responsibility in maintaining international peace and security. This means that the Council has more authority and power than the General Assembly. The Council is composed of five permanent members (the United States, England, France, China, and Russia) and ten non-permanent members. Non-permanent members are elected by the General Assembly and usually serve for two years. Half of the non-permanent members alternate every year. The permanent members have veto-power, and resolutions need unanimous consent in order to pass.

The Economic and Social Council discusses issues related to international economy, society, culture, and education.

The Trusteeship Council supervises countries under trusteeship in the U.N. trust territories.
The International Court of Justice issues rulings based on the United Nations Charter and International Court of Justice regulations. The judgment of the court is final and cannot be appealed by member states.
The Secretariat serves all administrative functions of the U.N. The Secretary General is nominated at the General Assembly based on the advice of the Security Council.
In addition to these main bodies, there are many subsidiary divisions in the U.N., including the United Nations Educational, Scientific and Cultural Operation (UNESCO) （联合国教科文组织）， the International Monetary Fund (IMF)（国际货币基金组织）， etc.

Q: What kinds of activities are the United Nations Peace-Keeping Operations involved in?

The first Peace-Keeping Operation(PKO) was the U.N. Truce Supervision Organization (UNTSO) that supervised the Palestinian ceasefire in 1948. The PKO had few activities until the 1970s. This is due to the fact that during the Cold War, the two superpowers, the United States and the Soviet Union, settled regional disputes not with the U.N. but autonomously.

However, with her power gradually decreasing, the Soviet Union could not help but become more cooperative with other countries through the U.N. After the collapse of the Soviet Union in 1991, the PKO became more active. More than half of the PKO's operations were concentrated in the first half of the 1990's, beginning with military surveillance of the Iran-Iraq War.

The major activities of the PKO are preventing disputes from escalating, policing ceasefires, and supervising fair elections. An agreement from or request by the countries involved in the dispute is required for the dispatch of the PKO. PKO members are prohibited from using weapons, other than in self-defense, and are obliged to observe neutrality under the guidance of the U.N. Secretary General.