ReadWriteQuiz
Chinese dictionary
slwork hard but to no avail; toil with no gain; all one's efforts came to naught
他派我们去干一件劳而无功的差使。
He sent us on a wild-goose chase.
老师虽尽力开导却劳而无功,我仍像以前一样糊涂。
The teacher's attempts at enlightenment failed. I remained as confused as before.