I would say because people separated from their kind and leading to speaking different. just like how people pick up accents when they go to the UK or other foreign countries.
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Answer:
b. He asked if I would help him with that essay as he would have to hand it in the tomorrow.
The right answer is letter c. This verb tense is formed by the auxiliar "have" or "has" plus the verb in participle form in this case is "won".