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Here are the answers: 1. C (should be "smile" -> "smile," or "smile and say" is incorrect. It should be "smile, and say" or rephrase the sentence.) However, correct answer should be A (If someone comes into the store) Correct sentence: If someone comes into the store, smile and say, "May I help you?" 2. B (should be "what was written") Correct sentence: If you do not understand what was written in the book, you could ask Mr. Pike. 3. C (should be "we can't continue") Correct sentence: If there isn't enough food, we can't continue our journey. 4. B (should be "if anyone phones" or "if anyone calls") Correct sentence: If anyone phones, tell them I'll be back at 11:00. 5. D (should be "haven't solved" or "don't solve") Correct sentence: I will come to meet Mr. Pike and tell him about your problems if you haven't solved them.