Rewrite the sentences. Use the words in brackets.
1. I'm sure he isn't here. (can't)
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2. I'm sure you know the answer. (must)
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3. I'm sure it isn't true. (can't)
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4. I'm sure they have a lot of money. (must)
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5. I'm sure he doesn't understand. (can't)
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6. I'm sure it's him. (must)
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