请问过去完成时的句子中必须有另外一个一般过去时的句子,还是可以单独存在,就是一个句子上来就是过完

过去完成时表示：过去的过去,因此句中通常有过去的时间或动作作为参照,如：
I had finished the job before yesterday.I had finished the job before he could offer some help.
但有些固定句式中必须用过去完成时：
1.wish,would rather 后跟宾语从句表示与过去事实相反的假设,这些从句就要用had done
I wish I had not made such a silly mistake in the last exam.
I would rather I had been scolded by my mother instead of my sister.
2.在no sooner...than,hardly...when 的主句中也必须用 had done
Hardly had he locked the door when he heard the bell rang.
还有一些句型平日多加留意