employees always prefer when their superiors communicate with them in private.爲什麽要加when?

when 在這裡是 pronoun 代名詞 = the time that ... = 當...的時候

Employees always prefer when their superiors communicate with them in private.
= Employees always prefer the time that their superiors communicate with them in private.
= 職員們都較愛 當他們的老闆 私下溝通的時候 (比起當面指責 的時候)

當然,用that也是可以但是意思會有點不同.


Employees always prefer when their superiors communicate with them in private.
= 職員們都較愛 他們的老闆 私下溝通的 這種經驗/情景/狀況

Employees always prefer that their superiors communicate with them in private.
= 職員們都較愛 他們的老闆 私下溝通的 這種做事方法

when=adv.=at what time; at the time that; considering that; ;
There are times when:-eg:-
There are times when I wonder what the superiors are communicating about my promotion in private.
(=got a raise in salary)
when is an adverb qualifying "prefer".

因為就是要加when