莫等闲白了少年头 don't dawdle the young head is soon white. for no reason
等闲 [书面语]1.(平常) ordinary; unimportant 等闲之辈 ordinary people2.(随便; 轻易) aimlessly; thoughtlessly 大好时光, 不可等闲度过。 don't fritter away your precious time. 莫等闲, 白了少年头。 don't dawdle, the young head is soon white.3.(无端; 平白地) for no reason; gratuitously
错过 miss; let slip 错过这趟汽车, 今天就走不成了。 if we miss this bus, we won't be able to go today. 我从来不错过踢足球的机会。 i never miss a chance of playing football. 这种机会不应错过。 such opportunities should not be missed [lost, wasted]
等闲视之 regard as unimportant; give someone [sth.] the go-by; regard it idly as of no importance; make nothing of; treat lightly; treat casually 这样的违法行为不可等闲视之。 such an illegal act should not be treated lightly