解析库 > PP2
If one could don magic spectacles-with lenses that make the murky depths of the ocean become transparent-and look back several centuries to an age before widespread abuse of the oceans began, even the most (i)_____ observer would quickly discover that fish were formerly much more abundant. Likewise,many now-depleted species of marine mammals would appear (ii)_____. But without such special glasses, the differences between past and present oceans are indeed hard to (iii)_____.
casual , plentiful , discern 显示答案