without fail

when you tell somebody to do something without fail, you are telling them that they must do it 务必;一定

I want you here by two o'clock without fail.
我要你两点钟务必来到这里.
You must be here by 8:30 without fail.
你务必在八点半之前到这儿.

always 总是;必定

He writes every week without fail.
他每周必定写信.

She sends me a christmas card every year without fail.
她每年都给我寄一张圣诞卡,从无遗漏.

déjà vu: the feeling that what is happening now has happened before in exactly the same way 似曾相识(的感觉)

I had a strong sense of déjà vu as I entered the room.
进这屋子时我有一种似曾来过的幻觉.