385.He could not plead ignorance as his excuse; he should have known what was happening in his department.
他不能以不知道做借口为自己辩护；他应该知道在自己的部门里发生了什么事。

六级词汇讲解:

plead意为“辩护；恳求”。如：
He pleaded with his mother to allow him to go to the circus.
他请求母亲答应他去看马戏。

ignorance意为“无知”。如：
I regret my ignorance on the subject.
我为自己对这个课题的无知感到遗憾。

第二个分句中的should have known即“should+have+过去分词”结构o should have done sth.表示“本应做某事而没有做”，shouldn’t have done sth.表示“做了本不应做的事”。如：
1) You should have come back earlier.
你本应早点回来。（实际上没早回来）
2) You shouldn’t have gone there yourself.
你本不应该自己去那里。（实际上自己去了）

英语六级考点归纳

excuse通常作名词，意为“借口”，如在本句中。但是excuse也可以作动词，表示“为……找借口；原谅”。如：
She stood up，excused herself and walked out of the meeting.
她站起身来，为中途离开致歉，然后走出会场。
Please excuse my bad handwriting.
请原谅，我的字写得不好。