I don't want to make it hot for you. But I won't tell you the true story of that till you return the letter to me.

我不想刁难你，但如果你不还给我那封信，我就不会告诉你那件事的实情。

youdao

If I have leftover food (food that I prepared previously and saved), then I heat it up using the microwave, stove, or oven. To heat up food means to raise the temperature, to make it hot.

如果我有剩饭剩菜，那么我就可以用微波炉/炉灶/加热。加热食物就是说升高温度来让它们变热啦。

youdao

Jiamin: I like swimming, but I don't like summer. It is too hot. I prefer winter. When it snows, I can make a snowman.

嘉明：我喜欢游泳，但是我不喜欢夏天。它太热了。我更喜欢冬天。当下雪的时候，我就可以堆雪人了。

youdao