1.Engineers spend much time and energy developing brilliant solutions.工程师们花费很多时间和精力来开发完美的解决方案。
2.He doesn't spend much time on his homework.他在作业上化的时间不多。
3.With the help of them, people don't need to spend much time on housework.有了它们，人们不必再花长时间做家务。
后面跟on sth，表示在某一件事上花费时间。
