Krashen holds that grammatical accuracy develops best through:

1. Krashen's second corollary says that when enough comprehensible input is given, i+1 is present. 2. The structures that acquirers are ready to learn are then found in the input. 3. He calls this a better method of developing grammatical accuracy than direct grammar teaching. 4. So direct grammar lessons are not the best route to accuracy. 5. Translation tasks and spelling tests are also form-focused practice rather than input. 6. The best route is plenty of comprehensible input. **Why the other options fail:** - Direct grammar teaching is the very method Krashen rates lower. - Translation exercises focus on form, not on understanding messages. - Spelling tests also test form and give no comprehensible input. _Source: Wikipedia, "Input hypothesis", section "Corollaries of the input hypothesis" (revision 1380165607)_