There are many times when I want to tell someone that I don't have enough energy to do something. These are close but not exactly what I want:
我太累。 I'm not too tired, I just don't have as much energy as I used to do what I want to do (like play basketball for 8 hours straight).
我的能力不够。Here, it's not that I don't have the ability to… I can do that, I just don't have the energy to do that (like play basketball for 8 hours straight).
Other contexts where I would like to use this phrase:
- "I have other responsibilities, so I don't have the time or energy to sit beside you and manage you."
- "The players aren't lazy, they just don't have enough energy to keep up with the other team."