SAT English grammar

Question

refer to the underlined sentence

Universities have historically offered a wide variety of continuing education classes, some of them are now offered over the Internet as well as in traditional classrooms.

a) NO CHANGE

b) classes, some of them that are

c) classes. Some of which are

d) classes, some of which are

I picked A; I do not understand why it is answer choice D. Please explain the difference of of them and of which. Thanks

Answer 1

The short answer is that "them" creates an independent clause while "which" creates a dependent clause.

If we keep "them" in the sentence as written, we need to either separate the second clause into its own independent sentence or change the comma to a semicolon. "Some of them are now offered over the internet as well as in traditional classrooms," gives enough information by itself to stand on its own. Granted, we need context clues to understand what "them" refers to, but it's still a full sentence.

If we use "which," however, we create a dependent clause that needs to be attached to an independent clause to be grammatically correct. In this case "which" functions as a modifier of "classes." For this reason, the clause containing "which" needs to be linked to the clause that it is modifying, which in this case means leaving it as a part of the same sentence.

This is a tricky one, and a pretty complicated explanation, so feel free to let me know if you need clairification!

Answer 2

The current sentence has a common splice--there are two independent clauses being joined by a comma, which is not grammatically correct. Had that comma been a period, then the sentence would be grammatically correct and no change would be necessary. However, changing the comma to a period was not an answer option, so you need to see which answer option would be best.

Option A is out because of the comma splice.

Option B also has a comma splice and is unnecessarily wordy

Option C is incorrect because now the second sentence is a dependent clause (also known as an incomplete sentence)

Option D is correct because by adding in "which," the writer has created a dependent clause, and the only way for a dependent clause to be a sentence is if it is joined with an independent clause. In this case, "Universities have historically offered a wide variety of continuing education classes" is an independent clause (because it can stand alone as its own sentence) and "some of which are now offered over the Internet as well as in traditional classrooms" is a dependent clause (it is an incomplete sentence). Together, the two clauses form a complete sentence: "Universities have historically offered a wide variety of continuing education classes, some of which are now offered over the Internet as well as in traditional classrooms."

Please let me know if you have any other questions or need additional help!

Answer 3

If you write "some of them" you are starting a new sentence, so you would need a period after the first sentence or a semicolon. "Some of them" functions as the subject, similar to saying "They." With a new subject comes a new sentence, so you cannot separate only with a comma. Choice D fixes this issue by using "some of which," which is basically an elaborate way of saying "which" and that is a preposition, so it does not start a new sentence but merely signals a new modifying phrase. Therefore, it can be separated with only a comma. For more help with writing, look me up on Wyzant! I'm Linda Rumpf, and I teach writing and reading.