If the underlying meaning of the sentence changes, then it is a restrictive clause.
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For more information see restrictive clause and the relevant subsection of relative clause.
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If the clause turns out to have been a supplement to the basic meaning of the sentence, then that means the clause was a non-restrictive clause.
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The less restrictive 3-clause BSD license is also used in some hardware projects, while the GNU GPL is often used for software components, such as models and firmware.
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Relatively speaking, United has a more relaxed scope clause that allows regional carriers to operate jets with up to 70 seats, whereas, Continental has a more restrictive clause of 50 seats.
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The second example uses a restrictive relative clause.
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The first example, with commas, and with three short intonation curves, contains a non-restrictive relative clause.
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Depending on context, a particular noun could be modified by either a restrictive or non-restrictive adjective clause.
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See if the clause requires extensive travel, loser-pays provisions or other overly restrictive conditions.