受害不浅 meaning in English

suffer not a little; suffer a lot

Smoking will catch up with you sooner or later
吸烟迟早会使你受害不浅。
Going down to the sea - side , i found a large tortoise or turtle ; this was the first i had seen , which it seems was only my misfortune , not any defect of the place , or scarcity ; for had i happen d to be on the other side of the island , i might have had hundreds of them every day , as i found afterwards ; but perhaps had paid dear enough for them
这是我上岛后第一次看到这种动物。看来，也许我运气不佳，以前一直没有发现，其实这岛上大鳖不少。后来我发现，要是我在岛的另一边居住，我每天肯定可以捉到好几百只，但同时因鳖满为患，将受害不浅。