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。