根据质量守恒定律，推测X应是（   ）

根据短文内容，判断下列各句正误。

    Here's the weather report for today. It's going to be dry and windy for most of the day. Because of the wind, it's going to be cooler than usual. And the wind is going to be stronger in the evening.

    Now the report for the weekend. Our Saturday morning is going to be cloudy with little rain. And it's going to be cooler than today. In the afternoon the clouds will lift and the sun will come out. We shall have a warm evening.

    On Sunday the weather is going to change again. It's going to be fine and hot. But at noon a wind will come and it's going to be stronger in the afternoon. It's going to be a little cooler in the afternoon.