essential/ɪ'sen∫əl/

a. important and necessary

a. 绝对必要的；非常重要的：[essential to（或for） sb/sth] Food is essential to life. 食物对于生命是绝对必要的。

◇[it is essential to do sth] It's essential to check again. 很有必要再检查一遍。

音组-ential/-'en∫əl/

confidential; essential; potential