一、同位語從句在句中的位置
1.一般情況下同位語從句跟在某些名詞(如news, idea, fact, promise, hope, message等)的後面，用以說明該名詞所表達的具體內容。例如：
The news that our women volleyball team had won the championship encouraged us all greatly.我們女排贏得冠軍的消息大大地鼓舞了我們所有人。
I've come from Mr Wang with a message that he won't be able to see you this afternoon.我從王先生那邊得知一個消息，他說他今天下午不能來看你了。
2.有時同位語從句可以不緊跟在它所說明的名詞後，而被別的詞語隔開，在語法上叫做分隔式同位語從句。例如：
The thought came to her that maybe she had left the door open when she left home.她突然想起可能在她離開家時沒把門關上。
The story goes that he failed in the College Entrance Examinations again.據說他高考又落榜了。
二、同位語從句前名詞的數
同位語從句前的名詞通常用單數形式，並且往往帶有限定詞(word除外)加以修飾。例如：
Where did you get the idea that I could not come?你在哪兒聽說我不能來？
Give me your promise that you will come to our party this evening.答應我，你今天晚上要來參加我們的晚會。
三、同位語從句連接詞的選用
在英語中，引導同位語從句的詞通常有連詞(that, who, whether)，連接副詞(how, when, where)等。例如：
They were all very much worried over the fact that you were sick.對你生病這件事，他們都很焦慮。
The question who should do the work requires consideration.誰該做這項工作，這個問題需要考慮。
We haven't yet settled the question where we are going to spend our summer vacation.我們還沒有決定到什麼地方去度暑假。
註：在名詞doubt「懷疑」後的同位語從句用whether連接；在no doubt「不懷疑」之後的同位語從句用that連接。例如：
We have some doubt whether they can complete the task on time.我們懷疑他們是否能準時完成任務。
There is no doubt that Zhang Wei will keep his promise.我們相信張偉會守信的。
同位語從句：that
有些名詞的後面可以接that引導的同位語從句：
We came to the decision that we must act at once.我們做出決定：我們必須立即行動。
He made a proposal that the meeting be postpone.他提議會議延期。
There was little hope that he would survive.他倖存的希望很小。