Free Grammar HelpWordsConjunctions and Clauses

Conjunctions are one of the 8 parts of speech. We need to talk about conjunctions together with clauses because clauses in sentences can be joined by punctuation (often a comma) or punctuation plus some kind of conjunction. Many grammar errors relate to the misuse of punctuation to join phrases and clauses.

Clause vs. Phrase

Let's review the difference between a clause and a phrase, also explained on the page on sentences. A phrase is any group of related words. A clause is a group of related words containing a subject and a verb. Incorrectly connecting clauses often leads to run-on sentences.

Comma and semicolon rules

RULE 1: Use a comma to separate main clauses joined by a coordinating conjunction (and, but, or, for, yet, and so.) Notice that the second clause also has a subject. If the subject is not present, then it's not a clause (it's a phrase), so you don't need a comma.

EXAMPLE: The students were delayed by the heavy rain, but they managed to get back to class on time.


  1. In compound sentences, when one or more of the main clauses are very short, you may omit the comma. Example: Ask no questions and you’ll be told no lies.
  2. You may use a semicolon to separate main clauses joined by a coordinating conjunction, especially when you have already used commas within the clauses themselves. Example: Harvard University, one of the best universities in the United States, was renowned for its Philosophy department; although Professor Leary was no longer teaching.
  3. You may use a semicolon in place of a comma to separate long coordinated clauses or to indicate a stronger pause between clauses. Example: Between reading, grammar exercises and watching videos, our English lessons consisted of worksheets, tests and quizzes; but still we had fun.

RULE 2: Use a semicolon to separate main clauses not joined by a coordinating conjunction.

EXAMPLE: Sometimes we work on grammar worksheets; other days we discuss our novel studies.

RULE 3: Use a semicolon to separate main clauses joined by conjunctive adverb.

(Conjunctive adverbs include: "also," "consequently," "finally," "furthermore," "hence," "however," "incidentally," "indeed," "instead," "likewise," "meanwhile," "nevertheless," "next," "nonetheless," "otherwise," "still," "then," "therefore," and "thus.") Conjunctive adverbs are adverbs that function as a conjunction (they join clauses and they modify a verb).

Examples of Conjunctive Adverbs

I took a course on grammar; also, I took a course on calculus.

I took a course on grammar; consequently, I write much better now.

I took a course on grammar; nevertheless, I still make mistakes.

I took a course on grammar; finally, I know how to use a semicolon.

I took a course on grammar; furthermore, I wrote a novel.

I took a course on grammar; hence, I am qualified to become an editor.

We went to the mountains to go skiing; however, the rain washed the snow away.

We went to the mountains to go skiing; incidentally, the resort was celebrating its anniversary.

I took a course on grammar; indeed, my teachers noticed the improvement.

I continue to learn more grammar rules; meanwhile, my writing assignments get harder.

I am becoming a skilled writer; nevertheless, I still use an editor.

I continue to proofread my essays; otherwise, I will hand in work with errors.

I look forward to graduating; still, I expect to continue to learn.

He told me he had learned all the grammar rules; then, I expect to see no mistakes in his writing.

English is a difficult language to master; therefore, expect to make mistakes.

I have completed my grammar course; thus, I will write much better.

Note that when the conjunctive adverb comes within the second main clause instead of at the beginning, the clauses still must be separated by a semicolon, and the conjunctive adverb set off by commas.

Example: Canadians spend millions of dollars for road-building; our roads, however, are still full of pot holes.

Subordinating Conjunctions

Subordinating conjunctions are different from conjunctive adverbs. A conjunctive adverb is primarily a transitional word carrying the thought from one main clause to the next. Subordinating conjunctions introduce subordinate clauses. Subordinating conjunctions include: "when," "although," "though," "since," "if," "because," "so that," "as," "after," "in order that", "while" and "unless." Subordinating conjunctions are used to express a logical relationship between clauses. Notice that the subordinate clause may come before or after the main clause.

Examples of subordinating conjunctions

I will be an expert grammarian when I complete the course.

Although I make mistakes now, I expect to be better later.

I am sad to see him go, though I know he will be happy.

I am happy to see her move to Zimbabwe, since she has been annoying me for two years.

If you give me five dollars, I will give you a piece of pie.

Because he studied at Oxford, I trust his grammar knowledge.

I sent her to the grammar course so that she will improve her writing.

As I am a dedicated teacher, I try to explain things as much as I can.

We will go for coffee after we have our meal.

In order that his writing improves, I have told him to take a course.

While we are studying in this course we must do our homework daily.

Unless you pay the tuition, you will not be registered.

Colon Rules

RULE 4: Use a colon to separate two main clauses, the second of which amplifies or explains the first.

EXAMPLE: The teacher posted a notice on the board: homework will be collected daily.

(The only other time you use a colon is to introduce a list. Do not use a colon to introduce speech or a quotation.)