crab中等

Pennsylvania farmers, to use one telling example, aren’t thinking about next year’s blue crab harvest in Maryland when they decide whether to spread animal waste on their fields, yet the runoff into nearby creeks can have enormous impact downstream.

举一个很能说明问题的例子：宾夕法尼亚州的农民在决定是否往田里施撒动物粪便时，并不会考虑马里兰州明年的蓝蟹收成，然而流入附近溪流的径流却可能对下游产生巨大影响。