世界各国领导人承诺打击核恐怖主义

in order to为了
例句：We started early in order to arrive before dark.
为了在天黑前到达,我们很早就动身了。
respond to对…作出反应〔回答〕
例句：The teacher responded affirmatively to the question that student put forward.
老师对那个学生的问题作了肯定的回答。

2. Chinese president Hu Jintao calls on the international community to respect the UN charter regarding the protection of nuclear materials.

call on要求, 请求
例句：He called on his friends to help him.
他向朋友求助。

3. We must eliminate the source of nuclear proliferation and nuclear terrorism; pursue the goals and principles of the U.N. Charter; adhere to the new security concept which emphasizes mutual trust, mutual benefit, equality and cooperation; continue using peaceful means to resolve hot issues and international disputes and create a favorable international environment for strengthening nuclear security.

adhere to遵循, 依附; 坚持
例句：They failed to adhere to our original agreement.
他们未能遵守我们原定的协议。

4. The UN Convention for the Physical Protection of Nuclear Materials, or the CPPNM, is the only legally binding convention related to the physical protection of nuclear materials.

relate to涉及, 关系到…
例句：The lawyer read all the papers relating to the case.
律师阅读了与该案有关的全部文件。

5. US president Barack Obama says nuclear materials remain vulnerable in front of what he describes as bad actors.

describe as描述为
例句：His employer had described him as lacking in initiative and drive.
雇主说他缺乏进取心和干劲。

6. There are still too many bad actors in search of these dangerous materials and these dangerous materials are still vulnerable in too many places.

in search of寻找
例句：The scientists are in search of a new element
科学家们正在寻找一种新元素。