When you attach a subordinate clause in front of a main clause, use a comma, like this:
Subordinate Clause + , + Main Clause.
Even though the broccoli was covered in cheddar cheese, Emily refused to eat it.
Unless Christine finishes her calculus homework, she will have to suffer Mr. Nguyen’s wrath in class tomorrow.
While Bailey slept on the sofa in front of the television, Samson, the family dog, gnawed on the leg of the coffee table.
When you attach a subordinate clause at the end of a main clause, you will generally use no punctuation, like this:
Main Clause + Ø + Subordinate Clause.
Tanya did poorly on her history exam Ø because her best friend Giselle insisted on gossiping during their study session the night before.
Jonathon spent his class time reading comic books Ø since his average was a 45 one week before final exams.
Diane decided to plant tomatoes in the back of the yard Ø where the sun blazed the longest during the day.
Subordinate clauses can begin with relative pronouns [and thus are called relative clauses, a type of subordinate clause]. When a subordinate clause starts with who, whose, or which, for example, punctuation gets a little bit trickier. Sometimes you will need a comma, and sometimes you won’t, depending on whether the clause is essential or nonessential.
When the information in the relative clause clarifies an otherwise general noun, the clause is essential and will follow the same pattern that you saw above:
Main Clause + Ø + Essential Relative Clause.
Nick gave a handful of potato chips to the dog Ø who was sniffing around the picnic tables.
Dog is a general noun. Which one are we talking about? The relative clause who was sniffing around the picnic tables clarifies the animal that we mean. The clause is thus essential and requires no punctuation.
When a relative clause follows a specific noun, punctuation changes. The information in the relative clause is no longer as important, and the clause becomes nonessential. Nonessential clauses require you to use commas to connect them.
Main Clause + , + Nonessential Relative Clause.
Nick gave a handful of potato chips to Button , who was sniffing around the picnic tables.
Button, the name of a unique dog, lets us know which animal we mean. The information in the relative clause is no longer important and needs to be separated from the main clause with a comma.
Relative clauses can also interrupt a main clause. When this happens, use no punctuation for an essential clause. If the clause is nonessential, separate it with a comma in front and a comma behind. Take a look at these examples:
After dripping mustard all over his chest, the man Ø who was wearing a red shirt Ø wished that he had instead chosen ketchup for his hotdog.
After dripping mustard all over his chest, Charles, who was wearing a red shirt, wished that he had instead chosen ketchup for his hotdog.
The word so serves as different parts of speech, most commonly as a conjunction, which joins two clauses in a sentence.
Use the comma when it begins what is a called a clause of result or effect. Here are examples:
It is difficult to relax during the week, so I like to get a way on weekends.
I will be on vacation next week, so please don’t contact me.
Don’t use the comma when you use so that or so to explain why something happened. These are called clauses of purpose:
We asked for approval early so that we could start on Monday.
The city wanted to tear down the building so the area could become a park.
I remember mentioning the meeting yesterday.
When “remember” is used with a gerund, it means “to remember that you have done something.” The sentence above means that I mentioned the meeting, and that I remember the fact that I did that.
He remembered to turn off the lights before he left.
When “remember” is used with an infinitive, it means “to remember that you need to do something.” The sentence above means that he remembered that he needed to turn the lights off.
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