nothing wrong.
brains means intelligence here.
Brains and brain work will become leading factor of economy.
智力、智力劳动将成为经济活动的主导因素.
When brute strength mattered more than brains,men had an inherent advantage.
在蛮力比脑力重要的年代,男人有天生的优势.
For all your energy and brains,you are gloriously obtuse about new realities.
尽管你有精力和头脑,但你对新现实的反应迟钝的可怕.