The weather in the south is warmer than ( that ) in the north一定要加that吗,什么情况可不加

题目

The weather in the south is warmer than ( that ) in the north一定要加that吗,什么情况可不加

答案

因为这是比较天气,如果没有that的话,那就比较对象不一致了,而且in the north是个后置定语,是修饰weather的,名词和形容词怎么比较呢.任何情况下都需要加,除非比较的对象一致.