Complex sentence: The World Bank is a strong supporter of the importance of economic growth for reducing poverty but does not believe that laissez-faire policies, if they allow large inequalities of wealth to develop, are an effective way to achieve this goal.
Split into simpler sentences: The World Bank is a strong supporter of the importance of economic growth for reducing poverty. However, the World Bank does not believe that laissez-faire policies, if they allow large inequalities of wealth to develop, are an effective way to achieve this goal.