inexhaustible

Solar energy is considered an inexhaustible resource compared to fossil fuels.

(Chinese) 与化石燃料相比，太阳能被认为是一种取之不尽的资源。

The young puppy seemed to have an inexhaustible supply of energy, playing for hours.

(Chinese) 那只小狗似乎有无穷无尽的精力，能玩上好几个小时。