求这道英语题的答案

Question

求这道题的答案。
Of the causes which have induced me to print this volume I have little to say; my own opinion is that it will ultimately do some service to science, and without that belief I _____ so thankless a task.
A. Would not have undertaken
B. Would not have been undertaken
C. Had not have undertaken
D. Will not have undertaken
并准备告诉我一下原因吧 谢谢！

Answer 1

选A，这题考核的是虚拟语气，表示本来不打算做但实际却做了。B和A很相近，只是多了been，不选B是因为不需要用被动语态。
最后句子意思是：如果不是有这信念，我就不会接受这种毫无回报的任务了----信念指的是：相信这样做对科学有益。追问

谢谢你哦，我还想问一下为啥句子开头是of the causes

本回答被提问者采纳

Answer 2

请问这是什么考试的题目呀？