Bartleby
Bartleby.com: The King's English: Grammar and Punctuation
Part of this chapter from the 1908 book by H.W. Fowler provides instructions for punctuating adjectival and adverbial clauses. However, there is a lot of other material on this page to scroll through.
Sophia Learning
Sophia: Clauses: Lesson 2
This lesson introduces clauses and discusses how to recognize them. It is 2 of 5 in the series titled "Clauses."
Sophia Learning
Sophia: Adjective Clauses: Lesson 5
This lesson introduces adjective clauses and their placement in a sentence. It is 5 of 5 in the series titled "Adjective Clauses."
Sophia Learning
Sophia: Noun Clauses: Lesson 1
This video-based lesson [4:00] goes over noun clauses and how they can be used. It is 1 of 2 in the series titled "Noun Clauses." Includes a short quiz. L.9-10.1b Phrases/Clauses
Sophia Learning
Sophia: Adverb Clauses
This lesson discusses adverb clauses and the associated subordinating conjunctions.
University of Ottawa (Canada)
University of Ottawa: Identifying Clauses
This site is set up like a quiz with ten questions involving various groups of words that must be identified as either a phrase or a clause.
University College London
University College London: Clauses and Sentences
This section of an online English-grammar book introduces and provides examples of different types of clauses. Because this is from a British source, it uses different terms to identify the types of clauses, calling an independent...
McGraw Hill
Mayfield Handbook: Restrictive and Nonrestrictive
This section of the Mayfield Handbook on restrictive and nonrestrictive modifiers and clauses features a definition with links to other parts of the sentence (modifiers, clauses, phrases) along with examples of restrictive and...
University of Calgary
The Basic Elements of English: Clause Identification
This page from an online grammar guide provided by the University of Calgary gives a definition and example of a clause.