Whether or not stretching prevents injuries is difficult to prove. If you stretch too much, or too hard, you actually can increase your risk of injury.

拉伸是否可以预防受伤是难以确认的，如果你拉伸太多，或过度，事实上会增加你受伤的风险。

youdao

Too little attention and it's difficult to achieve goals in life, too much attention and it's hard to break free from loops of negative thinking and feeling.

注意力过少的话，难以达到生活中的目标；注意力过多的话，难以从消极感受和思考中逃脱。

youdao

It is hard to build new roads or schools, and far too difficult to fire bad teachers.

ECONOMIST: California on the couch