This kind of training is ineffective, and wasteful of scarce resources
这种训练没有效率，而且是对稀缺资源的浪费。
Try to avoid wasteful duplication of effort.
尽量避免无用的重复劳动。
This practice is frowned upon as being wasteful
这种行为被认为是浪费而不获认可。
It is wasteful to leave water running from a pipe.
让水管里的水白白流掉，太浪费了。
As consumers, we are very wasteful.
我们消费者总是造成很多浪费。