Human activity is the main reason for this, the UnitedNations (UN) said.
联合国表示，人类活动是造成这一现象的主要原因。
2
Acronyms are words formed from the first letter of several words (such as UN for UnitedNations).
首字母缩写是由每个单词的第一个字母组合而成的，比如un就是指united Nations。
3
But Molyka wasn't at the UN headquarters in New York. Instead, she was participating in the annual Beijing Model UnitedNations last weekend at China Foreign Affairs University.