就2011年12月19日来函所提到的合作重点事项的翻译：Cooperation focused on matters referred to by letter dated December 19, 2011 什么意思？中文翻译英文，英文翻译中文，怎么说？

青云英语翻译

On December 19, 2011 letter referred to the cooperation priorities

Cooperation focused on matters referred to by letter dated December 19, 2011

Cooperation key item the incoming letter mentioned which on December 19, 2011

On December 19, 2011 as indicated in the letter received from the priorities for cooperation

Cooperation focused on matters referred to by letter dated December 19, 2011