endeavor做名词时意为：努力；尝试；任务.可数名词
单一的.努力用单数
1.Hard endeavor of 15 years is about to turn China's entry to the WTO into a reality .
经过15年的艰辛努力,中国加入世贸组织即将成为现实.
多种、多项努力用复数
Most of my endeavors are in collaboration with my wife, Jane Gray Morrison, and with colleagues and teams of researchers in dozens of countries.