This kind of training is ineffective, and wasteful of scarce resources
這種訓練沒有效率，而且是對稀缺資源的浪費。
Try to avoid wasteful duplication of effort.
盡量避免無用的重復勞動。
This practice is frowned upon as being wasteful
這種行為被認為是浪費而不獲認可。
It is wasteful to leave water running from a pipe.
讓水管里的水白白流掉，太浪費了。
As consumers, we are very wasteful.
我們消費者總是造成很多浪費。