heat build-up

例句：

1. 1.The hot summer sun is causing the ground to heat up quickly.
   炎热的夏天太阳使得地面迅速升温。
2. 2. The car's engine has a tendency to heat up during high-speed driving.
   汽车在高速行驶时发动机容易过热。
3. 3. During the long winter nights, the house gets very cold and needs to be heated up before we can sleep.
   漫长的冬夜，房子变得非常冷，需要加热后我们才能入睡。