The term 'adjective clause' (adjectival phrase, adjective phrase, or sometimes phrasal adjective) may refer to any one of three types of grammatical phrase. In syntax, the term adjectival phrase or adjective phrase refers to a phrase built upon an adjective, which functions as the head of that phrase. For example, the phrase much quicker than I is based on the adjective 'quick', and the phrase fond of animals is based on the adjective 'fond'. Such phrases may be used predicatively, as in They are much quicker than I (≈ they are quick) or they are fond of animals (≈ they are fond). When used attributively within a noun phrase, complex adjectival phrases tend to occur after the noun: I found a typist much quicker than I (compare I found a quick typist, where a simple adjective occurs before the noun). The words modifying the head adjective may be adverbs (much quicker, very pretty), prepositional phrases (fond of animals, happy about the news), or subordinate clauses (happy that you came).
There are many types of worksheets that deal with clauses on Busy Teacher so they have been broken into several subsections to make your search easier. This section is devoted to adjective clauses and currently has 16 worksheets. This is a general worksheet that talks about and has examples of many different types of clauses and sentence structures. Whether you use this as reference material for yourself or choose to include some of these sample sentences in your lessons, it can be a useful resource. In its entirety, it might be overwhelming for students so narrow down the material you want them to focus on and use that as a handout instead. Using these worksheets is so simple because they are all free and easy to download, adapt, and print. They can even be used as inspiration for your own worksheets and can definitely save you time when planning new lessons. Be sure to check back frequently for new worksheets and consider uploading your worksheets too.