study diligently(assiduously) and train (/practise) hard ? 這些工人由于～，已成為高度熟練的技術(shù)人員了。As a result of their assiduous study,these workers have become highly skilled technicians.
勤學(xué)苦練
studying diligently and training hard
勤學(xué)苦練
study and practice diligently;study diligently and train hard; diligent study and painstaking training
勤學(xué)苦練qín xué kǔ liàn
形容勤奮學(xué)習(xí)，刻苦訓(xùn)練。study diligently and train hard, diligent study and strenuous training, study and practise hard