think是就某种事实(肯定语气)作出评价,语气是肯定的,所以用that,而do u know含疑问语气,后面的语气是带疑问的,常用if/whether引导.
----如果提问是Do you know____ I should attend the leture?应该选A.whether
----如果提问是I leave for your judgement ____ you should do it应该选D,that.
宾语从句小结 [原]101270 | 12 一月,2006 12:36
一、当由陈述句充当宾语从句时,用that引导,that无词义,在口语或非正式文体中常省略.如：
She said that she would leave the message on the headmaster's desk.她说她会把留言条放在校长桌子上.
He said that he could finish his work before supper.他说他会在晚饭前完成工作
二、当由一般疑问句充当宾语从句时,用if或whether引导,意为“是否”.如：
Alice wanted to know if/whether her grandmother liked the bag.爱丽斯想知道她祖母是否喜欢这个包.
I don't know whether he'll come the day after tomorrow.我不知道他后天是否会来
但直接与or not连用时,往往用whether(if…or not也可以使用).如：
Let me know whether / if he will come or not.(= Let me know whether or not he will come )让我知道他是否能来.
I don't know whether / if he does any washing or not.(= I don't know whether or not he does any washing.)我不知道他在家洗不洗衣服.
I wonder whether we stay or whether we go.我想知道我们是去还是留.
三、如果宾语从句原来是特殊疑问句,只需用原来的疑问词引导.如：
Could you tell me where we will have the meeting this afternoon?你能告诉我我们今天下午将在哪儿开会吗?
I don't know who bought the present for me.Is it Jack?我不知道谁给我买了礼物.是杰克吗?