他们未能赢得所必须的2/3多数票.They failed to win the requisite twothirds majority.到山区去穿暖和的衣服是必须的.Warm clothes are a must in the mountains.他做工作缺乏成功所必须的信心.He won't go at a job with the confidence necessary for success....

“必须的”的英语可以翻译为：integrant，obligatory，pre-requisite，prerequisite ...