necessary
必要的 必需的 必然的英释
The booklet provides all the necessary information about the college..这本小册子提供了关于那所学院的所有必需信息。
No further changes were considered necessary..没有必要作出进一步改变。
The doctor says it may be necessary for me to have an operation..医生说我可能需要做手术。
if necessary,如果必要的话
necessary for,所必需；对…是必要的
necessary condition,必要条件，充分必要条件
when necessary,在必要的时候
as necessary,必要时
absolutely necessary,绝对必要
necessary and sufficient condition,充要条件；必要且充分的条件
where necessary,必要时；需要时；必要地方
sufficient and necessary condition,充要条件；充分必要条件
necessary evil,n. 无可避免之灾祸
necessary connection,必然联系
