\(\left(3\dfrac{1}{4}:x\right)\).\(\left(-1\dfrac{1}{4}\right)\) = \(-\)\(\dfrac{5}{3}\) \(-\) \(\dfrac{5}{6}\)

There is a mistake in each of these sentences. Underline the mistake and then correct it.

1. It has started raining an hour ago.

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2. I knew Hoa for some months.

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3. We didn't see Nga since Monday.

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4. Lan was in the USA for 2 years.

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5. I have gone to bed at 10 o'clock last night.

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6. They moved to London for 2003.

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7. How long have you learn English?

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8. Peter was ill for a week.

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\(\dfrac{4}{9}\) : \(\left(-\dfrac{1}{7}\right)\) + 6\(\dfrac{5}{9}\) : \(\left(-\dfrac{1}{7}\right)\)