Relative clauses and relative pronouns
There are two kinds of relative clauses.
Carbon is an element which has an atomic weight of
A figure which has all sides equal in length is called an equilateral figure.
Robotics is the study of robots, which are electro-mechanical devices that can be programmed to perform manual tasks.
An insect, which is a small animal, has a body divided into three parts: head, thorax and abdomen.
Forms of relative pronouns in relative clauses
-who and that are used in relative clauses when describing people
-who and that can be used in place of noun subjects or subject pronouns. (I, you, he, etc.) and cannot normally be omitted.
-who and that remain unchanged whether they refer to masculine, feminine, singular or plural.
-In a defining relative clause that is interchangeable with who, but who is more common.
e.g. a person who/that writes AI programs is usually
a computer scientist.
-In a non-defining relative clause only who (not that) is possible.
e.g. Alan Turing, who wrote an article entitled
"Computing Machinery and Intelligence" in
1950, is considered to be the "father" of
-which and that are used in relative clauses when describing things and animals.
-In a defining relative clause that is interchangeable with which.
e.g. Many high-technology companies are involved in AI research to develop techniques which/that can improve their productivity and products.
-In a non-defining relative clause only which (not that) is possible.
e.g. Planning and decision support, which is an area of AI research, can help managers evaluate information, choose a goal, or reach a conclusion.
Notice these changes:
e.g. There are many universities in the U.S. and other countriesin which/ where AI research is being conducted.
but Acoustics is a branch of Physicsin which the properties of sounds are studied. (why not "where"?)
Airports are placesat which/ where special attention is paid
to the weather.
but The temperatureat which water boils depends on the pressure. (Why not "where"?)
e.g. A transducer is a deviceby means of which/ whereby a non- electrical signal, such as sound, light, heat, etc., is converted into an electrical signal, or vice versa.
Jupiterof which the mass is two and a half times the mass of all the other planets put together is the largest planet of the Solar System.
Jupiter the massof which is
Jupiterwhose mass is .
(The Division of English for Science and Technology,
Chulalongkorn University Language Institute)
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