Population is such a serious problem that we should take action.(改为同义句)改为population　　is　so　什么四个空we　should　take　action

Population is such a serious problem that we should take action.(改为同义句)改为population　　is　so　什么四个空we　should　take　action
Population is such a serious problem that we should take action.(改为同义句)
改为population　　is　so　什么四个空we　should　take　action

Population is such a serious problem that we should take action.(改为同义句)改为population　　is　so　什么四个空we　should　take　action
Population is so (serious a problem that) we should take action.
人口是如此严重的一个难题以至于我们应该采取措施了.