必須的的英文，必須的的翻譯，怎麽用英語翻譯必須的

英文：integrant； obligatory； pre-requisite； prerequisite；must

Warm clothes are a must in the mountains.

到山區去穿暖和的衣服是必須的.

He won't go at a job with the confidence necessary for success.

他做工作缺乏成功所必須的信心.