They are great at hitting muscles that need more work, and they're more effective in controlling specific volume targets for any given muscle.

它们能很好地锻炼那些需要更多锻炼的肌肉，并且能更有效地对你任何的目标肌肉进行有针对性的训练。

The real situation is fiendishly complex and involves pretty hairy quantum mechanics, but in the end, the electron is only allowed to occupy very specific volumes of space around the nucleus, and those depend on the electron's energy.

实际情况极其复杂，涉及到相当复杂的量子力学，但最终，电子只能占据原子核周围非常特定的空间，且这些空间取决于电子的能量。