Lesson 12 (Dec. 1)

1. Lesson 12 (Dec. 1) Relative Clauses (2)

2. Relative Clauses • Recall: • Relative clause which follows the subject noun of the main clause: • An object which is left in the sun becomes hot. • Relative clause which follows the object noun of the main clause: • This paper is made from alfalfawhich is expensive. • Prepositional relative clauses: • The river from which this water is taken is polluted. • That farm produces alfalfa from which this paper is made.

3. Relative Clauses with whose & of which • Example: • Venus is a planet. • The surface temperature of the planet is at least 200°C. • Venus is a planet(the surface temperature of the planet is at least 200°C). • Venus is a planetof which the surface temperature is at least 200°C. • Venus is a planetwhose surface temperature is at least 200°C. • Both whose and of whichare acceptable here. However, whoseis usually reserved for people. • In the above example, Venus is treated as a person. main clause

4. Relative Clauses with whose & of which • Example: • The rectifier is an electronic device. • The effect of the device is to restrict current to one direction. • Using whose on an inanimate object is not acceptable: • The rectifier is an electronic device whose effect is to restrict current to one direction. • In such cases, always use of which: • The rectifier is an electronic device of which the effect is to restrict current to one direction. main clause

5. Relative Clauses with whose & of whom • Example: • Einstein was a 20th Century physicist. • His Theory of General Relativity was an important discovery. • For a person, whose is the obvious choice: • Einstein was a 20th Century physicist whose Theory of General Relativity was an important discovery. • Very rarely, one may also use of whom: • Einstein was a 20th Century physicist of whom the Theory of General Relativity was an important discovery. • Of which is never used on a person. main clause

6. Reduced Relative Clauses • Passive relative clauses are sometimes reduced: • Our first example: • An object is left in the sun. It becomes hot. • An object which is left in the sun becomes hot. • An object left in the sun becomes hot. • Another example: • Paper which is made from alfalfa is expensive. • Paper made from alfalfa is expensive.

7. Reduced Relative Clauses • Paper made from alfalfa is expensive. • Notice that only which + beand who + be can be reduced, i.e. which is, which are, which was, which were. • We use reduced passive relative clauses because they are shorter and because which is orwhich are are uninformative. • Our other examples: • A bottle which is dropped on a stone floorusually breaks into pieces. • A balloon which is filled with a gas lighter than air rises off the ground. • A diseases which is caused by a virus is often difficult to cure. made is not a verb here. It is a past participle. One can think of it as an adjective describing the paper.

8. Reduced Relative Clauses • Not all passive relative clauses can be reduced. • Passive relative clauses beginning with a preposition cannot be reduced. The following reduction is wrong! • The tarmac with which these roads are surfaced allows higher speed than stones. • The tarmac with these roads are surfaced allows higher speed than stones. 

9. Active Relative Clauses • Like passive clauses, active relative clauses in scientific English usually begin with which. They can also begin withwho, where, whose, that, or a preposition+ relative. • The Ford iMax is a mid-size family car. It seats 5 people. • The Ford iMax is a small family car which seats 5 people. • The man teaches physics.He is a graduate of NCNU. • The manwho teaches physics is a graduate of NCNU. • The room has only one small table. He works in the room. • The room in which he works has only one small table.

10. Reduced Relative Clauses • Some active relative clauses can also be reduced. • The manwho teaches physics is a graduate of NCNU. • The manteaching physics is a graduate of NCNU. • In this case the wh-word (which, who, etc.) is omitted and the verb is changed to a present participle (verb+ing): which/who verb  verb+ing • He has a form of cancer which requires surgery. • He has a form of cancer requiring surgery.

11. Reduced Relative Clauses • The manwho teaches physics is a graduate of NCNU. • The manteachingphysics is a graduate of NCNU. • The above reduction is applied when the wh-word is the subject of the verb that follows it. • “who” is the subject of the verb “teaches”. • “who” replaces the subject “He” in the original secondary clause: He teaches physics. • When the wh-word is the object noun of the verb that follows it, the wh-word can be simply omitted without any change to the verb: • This is the pen which he uses. • This is the pen he uses.

12. Other wh-words • Where is used for places in passive relative clauses, and is a substitute for in which, at which: • The room has only one small table. He works in the room. • The above can be rephrased in two ways: • The room in which he works has only one small table. • The room where he works has only one small table. • Another example: • I often go to the library. I can find many interesting books in the library. • I often go to the library in which I can find many interesting books. • I often go to the library where I can find many interesting books.

13. Other wh-words • wherein = in which • A university wherein students are excited about learning is a good university. • whereby = by which • A waveguide is a structure whereby signals can be transmitted. • The paper proposes a method whereby the filter’s performance can be optimized. • whereby = because of which • The university has introduced a new rule whereby all TAs must undergo training.

14. That instead of wh-words • The wh-words we have discussed are called relative pronouns, i.e. subject or object nouns in relative clauses. • subject: An object which is left in the sun becomes hot. • object: This is the pen which he uses. • subject: The manwho teaches physics is a graduate of NCNU. • object: The room where he works has only one small table. • In some relative clauses, that is used as the relative pronoun instead of a wh-word: • This is the best movie that I have seen. • The terms thathave been omitted in the equation are negligible.

15. That instead of wh-words • As a general rule, that is used in a relative clausereferring to persons or things that you are defining: • The terms that have been omitted in the equation are negligible. • The above relative clauses tells the reader about those terms for the first time. • That is also used where the person or thing is specific: • This is the best movie that I have seen.

16. That versus Which • American academics and editors are especially particular about when to use that, and when to use which. • The traditional approach to this question is to use thatwith restrictive relative clauses and whichwith nonrestrictive relative clauses. • A restrictive clause restricts the identify of the subject: • The painting that was hanging in the room was stolen. • Without the restrictive clause, the reader would not know which painting you are talking about. • A nonrestrictive clause may tell us something interesting about a subject, but it does not define that subject. The subject probably has already been mentioned before. • The painting, which was hanging in the foyer, was stolen.

17. That versus Which Which! That! More about this in 科技英文(二)

18. Nested Relative Clauses • Nested relative clauses combine more that two simple sentences: • We are asked to read a paper. • The paper was written by a graduate student. • The student studies composite materials. The paper was written by a graduate student who studies composite materials. We are asked to read a paper which was written by a graduate student who studies composite materials.

19. Nested Relative Clauses • Reduced relative clauses are especially useful in such cases: We are asked to read a paper which was written by a graduate student who studies composite materials. Reduced: We are asked to read a paper written by a graduate student studying composite materials.