Subordinate Clause

A subordinate clause supports the main clause in a sentence by functioning as an adverb, an adjective, or a noun.

Subordinate Adverbial Clause

• I fished until the Sun went down . (The subordinate clause "until the sun went down" modifies the verb "fished." It is an adverbial clause.)

Subordinate Adjective Clause

• The bull that charged us is back in the field. (The subordinate clause "that charged us" describes "the bull." It is an adjective clause.)

Subordinate Noun Clause

• Whoever dislikes the new timings is more than welcome to leave. (The subordinate clause "Whoever dislikes the new timings" is the subject of this sentence. It is a noun clause.)

The Link between a Subordinate Clause and an Independent Clause

When a subordinate clause is used as an adjective or an adverb, it will usually be part of a complex sentence (i.e., a sentence with an independent clause and at least one subordinate clause).

• I fished until the sun went down . (subordinating conjunction in bold)
• The bull that charged us is back in the field. (relative pronoun in bold)

Subordinating Conjunctions and Relative Pronouns Used with Subordinate Clauses

• after, although, as, because, before, even if, even though, if, provided, rather than, since, so that, than, though, unless, until, whether, while

• how, that, what, when, where, which, who, whom, whose, why

• whoever (who + ever)
• whosever (whose + ever) (Spelling rule: Don't allow ee.)
• whosoever (who + soever)
• whosesoever (whose + soever)

Why Subordinate Clauses Are Important

(Question 1) When do you use a comma with a subordinate clause?

By far the most common question related to subordinate clauses is whether to offset one with a comma (or commas).

Here are the rules:

(Rule 1) If your subordinate clause is a fronted adverb, use a comma.

When the subordinate clause starts with a subordinating conjunction (e.g., unless, because, as, until), it will be functioning as an adverb. When the clause starts the sentence, use a comma. If it ends the sentence, do not use a comma. For example (subordinate clauses shaded):

• Until there are no more shoppers , keep singing. (The subordinate clause is at the start, so a comma is needed.)
• Keep singing until there are no more shoppers . (The subordinate clause is at the end, so a comma is not needed.)

For example (adverbial phrases in bold):

• At 4 o'clock, the bell will ring.
• The bell will ring at 4 o'clock.

(Rule 2) If your subordinate clause is a nonessential adjective, use a comma.

When the subordinate clause starts with a relative pronoun (e.g., which, who), it will be functioning as an adjective. Do not use a comma before your relative pronoun if the clause is essential for meaning. However, do use a comma if the clause is just additional information.

For example:

• My sister who lives in Moscow is getting married. (From this we can infer that there is at least one other sister who doesn't live in Moscow. The clause is essential for meaning. It identifies what it modifies, i.e., it specifies which sister.)
• My sister Rebecca, who lives in Moscow , is getting married. (This time, the clause is just additional information. It needs commas.)

Top Tip

If you'd happily put parentheses () around your clause, it needs commas.

(Commas, after all, are just a type of parenthetical punctuation.)

(Question 2) Can you start a sentence with "which"?

You cannot start a sentence with who or which unless it is a question (i.e., an interrogative sentence). For example:

• I enjoy weeding. Which is helpful because I have a large garden.

Key Points

• If your subordinate clause is a fronted adverb, offset it with a comma.
  • When the cake is brown, remove it from the oven.
• If your subordinate clause is at the back, don't use a comma.
  • Remove the cake from the oven when it is brown.
• If your subordinate clause is an essential adjective, don't use commas.
  • My sister who lives in Boston gave me her laptop. (I have more than one sister. The Boston-based one gave me her laptop.)
• If your subordinate clause is a nonessential adjective, use commas.
  • My sister, who lives in Boston, gave me her laptop. (I have one sister. Oh, by the way, she lives in Boston.)
• Don't start a sentence with "which."

This page was written by Craig Shrives.