12 Grammar and punctuation Scientific journals(as well as thesis committees and employers) want perfect pelling and punctuation in papers submitted to them; so do we 12.1 Parentheses Parentheses enclose material that can be left out. If the parentheses and all the material within them were omitted the sentence should still make sense and be correctly punctuated. Thus RIGHT: This is a sentence.(So is this. )This is,too WRONG! This is a sentence So is this. )This is, too RIGHT: This is a sentence(and this is more of it). This is,too 12.2 Commas Commas do not denote pauses in speech. Their purpose is to make the meaning clearer. Use commas to keep sentences from being misunderstood Often- not always- you will end up putting them where you would pause if speaking Commas are often used like parentheses to mark material that can be left out. Thus Chomsky, who invented transformational grammar, was a Har- vard Junior Fellow in the early 1950s Chomsky is Chomsky whether or not we know he invented TG. The student who left his books here should come and get them (No commas here because we cannot leave out left his books here: if we did. the sentence would not reveal which student was 12.3 Who vs whom The difference between who and whom is exactly the same as the difference between he and him12 Grammar and punctuation Scientific journals (as well as thesis committees and employers) want perfect spelling and punctuation in papers submitted to them; so do we. 12.1 Parentheses Parentheses enclose material that can be left out. If the parentheses and all the material within them were omitted, the sentence should still make sense and be correctly punctuated. Thus: right: This is a sentence. (So is this.) This is, too. wrong! This is a sentence (So is this.) This is, too. right: This is a sentence (and this is more of it). This is, too. 12.2 Commas Commas do not denote pauses in speech. Their purpose is to make the meaning clearer. Use commas to keep sentences from being misunderstood. Often — not always — you will end up putting them where you would pause if speaking. Commas are often used like parentheses to mark material that can be left out. Thus: Chomsky, who invented transformational grammar, was a Har￾vard Junior Fellow in the early 1950s. (Chomsky is Chomsky whether or not we know he invented TG.) The student who left his books here should come and get them. (No commas here because we cannot leave out “who left his books here;” if we did, the sentence would not reveal which student was meant.) 12.3 Who vs. whom The difference between who and whom is exactly the same as the difference between he and him. 11