Without such data, predictive analytics become very difficult.

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"If we start with the actions next week, which we intend to, to move from a conceptual discussion to implementation phase, we'll start to make commitments that then become very difficult to come out of, " he said.

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It strikes me that trying to define where the front lines are might become a very difficult problem in wartime.

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Philippe Conraud, Oxfam country director in Mali, said if the traders did not return soon, it could become "very difficult for people to get enough food to feed their families".

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"But unless we are all working together it will become a very, very difficult challenge for us to address, " he admitted.

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Mechanical is very difficult to become.

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To become a doctor: 4 years of college, 4 years of VERY difficult med school, 3-7 years of residency.

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It's become a very unpleasant business and running against Mitch McConnell would be an extraordinarily difficult and grueling experience.

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We are a very long way away from things picking up and I expect them to become substantially more difficult before they do.

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The very fact that investors are even considering these approaches shows how difficult their life has become.

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