21. Rod Ellis (2006) offered some of his own answers to questions about when and how toteach grammar. Which of the following statements is not his assertion? (A) Corrective feedback can facilitate acquisition if itinvolves a mixture of implicit and explicit feedback. (B) Explicitgrammar teaching is more effective at the beginning levels than intermediate to advanced levels. (C) Both deductive and inductive approaches can be useful, depending on the context and purpose of instruction. (D) Both form and meaning should be emphasized; learners need to have the opportunity to practice forms in communicative tasks.