The millions of calculations invovled had they been done by hand,___all practical value by the time they were finished.A.had lost B.would have C.would have lost D.should have lost這里面我想知道C D兩個(gè)答案的區(qū)別，我的理解是should have done 和would have done 都是半情態(tài)動(dòng)詞過去式加完成體，所以都表示本該做而沒做，而全情態(tài)動(dòng)詞加完成體表示對過去事實(shí)的推測。那么我想請教一下這道題應(yīng)該選什么，為什么？多謝大家了。。。

熱心網(wǎng)友

The millions of calculations involved,had they been done by hand, ____ all practical value by the time they were finished。[譯文]有關(guān)的數(shù)以百萬次的計(jì)算，如果用手工進(jìn)行，到它們完成時(shí)就失去了全部實(shí)用價(jià)值。1。should+have+done在肯定句中表示“該做的事情沒有做”,在否定句中表示“已做了不該做的事”。通常用來表示一種義務(wù)、自責(zé)或提出委婉的批評。如: I regretshavingsleft the work unfinished; I should have planned everything ahead carefully。我后悔把工作半途而廢；我本來應(yīng)該事先仔細(xì)把每件事安排好。2。您的題目僅表示對過去的虛擬,故只能選C。would have lost。 3。情態(tài)動(dòng)詞后面加動(dòng)詞完成式，有不同意義。　　must have done表示一定做過某事；　　should have done表示本應(yīng)該做某事，含有義務(wù)、自責(zé)或批評的意思；　　would have done主要用于虛擬語氣，表示對過去的虛擬；　　may have done表示可能已經(jīng)作過某事。

熱心網(wǎng)友

選cshould有應(yīng)該的意思would比較合適