有意要做某事 mean to do

对某人没有必要做某事 There's no need for sb. to do

有必要做某事 be necessary to do sth ; need to do sth ; It's necessary to do sth ; need to do sth./need do sth

没有必要做某事 There is/was no need to do sth ; There is no need to do

感觉有必要做某事 feel obliged to do sth

某人有必要做某事 Someone need to do something

有某事要去做 There will be sth to do

认为有必要做某事 consider it necessary to do sth