The simplest way to combine two simple sentences together is to link them with a conjunction. Common conjunctions are "and," "but," "or" and "so." An example of this kind of sentence would be: "I like to swim, but I enjoy running." To put an interesting twist on teaching students this method, stage a combining sentences "race." Split your class into two or three teams and have each team line up single file. Give two simple sentences for one member of each team to write on the board and combine. The team member with the best sentence using the appropriate conjunction gets the point. A team member can decide to pass on the round, and pass off his or her turn to the next teammate, but only gets one chance to do so.
Typically, the semicolon (;) and the colon (:) are the most effective kinds of punctuation to use to form a sentence using proper grammar. Students are often confused by the comma when it comes to combining sentences, so make sure to address that the comma is too weak, often leading to run-on sentences that can confuse the reader. Semicolons can connect any two sentences that have an association in meaning with each other, as in, "He's not my boyfriend; he's my older brother." The colon can be a little more difficult to explain, as it should only be used in a cause and effect manner. For example, the sentence "I like bacon: puppies are fluffy" would be incorrect, as neither sentence has any logical relation to the other. A correct sentence using the colon would be "I like bacon: I think I'll cook it for dinner." Because you like bacon, therefore, you think it appropriate to cook it for dinner. It's helpful teach your students to insert mentally "(first sentence), because of (second sentence)" to test the logic of the complex sentence.
Sometimes, two simple sentences can be combined so that one simple sentence is hidden within the other. You can do this using dashes — dashes being a form of conjunctive punctuation like the semicolon and colon — which typically are not necessary for the sentence to make complete, logical and grammatical sense. A simple sentence, set off by commas, can also be an effective way of combining two simple sentences. For example, the sentences "Sara always wore pink" and "Sara wanted to be a ballerina" can be combined in one sentence that retains the same meaning: "Sara, who always wore pink, wanted to be a ballerina." Type up silly sentences and have your students use punctuation to make them have logical sense with one another. Read your paragraphs out loud once everyone is finished.
Take one of the sentences and reduce it to a separate phrase that connects in meaning to the other unchanged simple sentence. There are four types of this kind of phrases: a participial phrase, gerund, infinitive phrase and prepositional phrase. For example, the sentences "She saw the movie star in the restaurant" and "She was excited" could be combined to say "She was excited to see the movie star in the restaurant." In order for this phrases to make sense to your students, find a section of literature and print out copies for the entire class, making sure that the selection has a variety of these kinds of sentence structures. Have your students comb through the reading selection to pick out how many of these phrases they can properly identify, annotating it on their handout.
Like combining sentences using reduction, students can put simple sentences together by attaching a subordinate clause to one sentence to depend on the other, second simple sentence. Typical subordinate clauses include conjunctive words such as "when," "what," "if," "then," "that," "although," "therefore" and "however." A way you can teach your students how to use subordinate clauses properly is to have them write their own poetry, first only writing simple sentences. Then, have them combine those sentences using the subordinate clauses. Have them compare with one another.