37. But for your timely help at the end of last semester, I ________ the deadline for the term paper then.
(A)missed
(B)would miss
(C)shall miss
(D) would have missed

[與過去事實相反]

But for (Without) +noun

                                     ,S  + (would/could/might/should) +現在完成式have p.p.  

Had it not been for + noun

37. But for your timely help at the end of last semester, I ________ the deadline for the term paper then.

翻譯:上學期末要不是您的及時幫助下，我可能會錯過當時的學期論文截止日期。

"But for" 是一個固定用法，在英文中主要表示「要不是」或「如果沒有...的話」，通常用在假設語氣中，與未發生的事實相反，可以替換成 without, if it were not for, 或 were it not for，

，例如 "But for your help, I would have been in trouble" (要不是你幫忙，我早就麻煩了). 

精選例句：

1. 要不是他（現在）很窮，他就會出國去。
But that he is poor, he would go abroad.

2. 要不是他當時很窮，他早就出國去了。
But that he was poor, he would have gone abroad.

https://www.nani.com.tw/slearn/sleng/eng_d/Chapter04/Chapter04_2.htm

But for your timely help at the end of last semester