无霜期的英文：
frost-free season
frost-free growing season
n. 严寒；霜；冷淡
v. 结霜（于）；冻坏
- Frost is an enemy of flowers.
霜冻是花卉的大敌。 - Frost caused the split in the rock.
霜冻使岩石裂了一条缝。 - The crops were blasted by frost.
作物被霜冻毁了。
adj. 自由的；免费的；空闲的；任意的；免税的；游离的
adv. 免费地；自由地
v. 释放；免除；使自由，解放
- Freedom is not free.
自由不是无偿的。 - Be covered by free Medicare / be entitled to free medical care
享受公费医疗 - It depends on free oxygen or air.
它依靠大量的氧或者空气。
n. 季节；时节；节期，时令
v. 给…调味；风干；（使）适应；（使）习惯
- season cracking
风干裂缝, 应力腐蚀裂纹, 季裂 - shooting season
狩猎期 - This is not the season for harvest.
现在不是收获的季节。