The National Council of Teachers of English (NCTE) recommends three of the six sentence-composing strategies for building better sentences, all of which are frequent activities in all of the sentence-composing books: expanding, combining, and imitating. In addition to those three activities, the books also feature recurring activities in matching, unscrambling, and exchanging to deepen and solidify students’ skill in building sentences like those of authors. Click here for a description of each of the six activities.
“Inexperienced writers find it difficult to make changes in the sentences that they have written. Expanding sentences, rearranging the parts of a sentence, combining sentences–these skills do not come easily. So any exercises that help students acquire sentence flexibility have value. Two methods have yielded good results. One is sentence combining: students start with simple exercises in inserting phrases [expanding] and combining sentences and progress towards exercises in embedding one clause in another. Another approach is for students to imitate model sentences; when students read a model passage and then write their version of it, imitating its grammatical features, they integrate reading skill, writing practice, and grammatical understanding.”
(from the National Council of Teachers of English Assembly on the Teaching of Grammar)