This section is from the book "Lessons In English", by Chestine Gowdy, Lora M. Dexheimer. Also available from Amazon: Lessons in English.
1. I know the man that passed us.
Analyze the sentence. What clause do you find? What kind of clause is it? Why?
What part of speech is the word that? Why? What noun in the main proposition names the same subject of thought? Read the sentence, putting the words the man in the place of the pronoun that. Write what you have read. You should have written the following: I know the man. The man passed us.
Put the pronoun he in the place of the pronoun that; thus, I know the man. He passed us.
You see the words who passed us are a clause joined to the noun man, while the expressions, The man passed us and He passed us, are complete sentences and are not joined to any word. What word has been changed in order to change the clause to an independent sentence? What, then, must connect the clause to the noun man?
2. I have seen the place about which the story tells.
Analyze the sentence. What clause do you find? To what is it added? What part of speech is which? What noun in the main proposition represents the same subject of thought? Substitute the words the place for which; thus, I have seen the place. About the place the story tells. How many sentences in the new expression? Put the subject of the second one first.
Since the words, about which the story tells, are a clause added to the noun place, while the words, The story tells about the place, are an independent sentence not joined to any word, what word must join the clause to the noun?
3.Whittier, who wrote Snow-Bound, was a Quaker.
Analyze the sentence. Put the noun Whittier in place of the pronoun who; thus, Whittier - Wliittier wrote Snow-Bound - was a Quaker. You see the words, Whittier wrote Snow-Bound, are a complete sentence, coming between the parts of another sentence. In the same way, if you put the pronoun he in place of the pronoun who, the clause becomes a sentence. What must join the clause to the noun Whittier?
4. He whom we passed is an author.
To what is the clause joined? Put the pronoun him in place of the pronoun whom. What does the clause become? Read this sentence, putting the subject first. What must join the clause to the pronoun he?
The words that, which, who, and whom in these sentences are called conjunctive pronouns. Why?
142. A Conjunctive Pronoun1 is a pronoun that joins an adjective clause to a noun or pronoun.
Notice that a conjunctive pronoun has two uses: (1) it has a noun use in the clause, and (2) it joins the clause to a noun or another pronoun. Try to tell what noun use each conjunctive pronoun has in the four sentences studied in Exercise 177.
The conjunctive pronoun who is used to refer to persons; which is used to refer to things, and that is used to refer to either persons or things. Some persons prefer to use that in limiting adjective clauses (§ 118) and who or which in purely descriptive clauses (§ 119), but many good writers do not follow this practice.
1 These pronouns are often called relative pronouns.
 
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