A sunny day in winter is colder than a sunny day in summer. This is because the summer day is longer, everything has a longer time to warm up and the sun shines more directly on the earth.

• 一个久天的睛日要比一个夏天的晴日冷，因为夏天的白天比较长一切东西受热的时间较长，太阳直射到地球上。