【GMAT句子改错】Around 1900, fishermen in the Chesapeake Bay area landed more than seventeen million pounds of shad in a single year, but by 1920, overfishing and the proliferation of milldams and culverts that have blocked shad migrations up their spawning streams had reduced landings to less than four million pounds.
Around 1900, fishermen in the Chesapeake Bay area landed more than seventeen million pounds of shad in a single year, but by 1920, overfishing and the proliferation of milldams and culverts that have blocked shad migrations up their spawning streams had reduced landings to less than four million pounds. （OGV262）
A that have blocked shad migrations up their spawning streams had reduced landings to less
B that blocked shad from migrating up their spawning streams had reduced landings to less
C that blocked shad from migrating up their spawning streams reduced landings to a lower amount
D having blocked shad from migrating up their spawning streams reduced landings to less
E having blocked shad migrations up their spawning streams had reduced landings to an amount lower
前后有对比：以前是每年可以海洋捕捞17million，但是由于过度捕捞和使用拦截鱼群的装置，到了1920年只剩下每年4million了；
have blocked 一般现在时，时间发生在当下，且对现在有影响，和1920年时间点不符
having blocked一般现在时，having特意用了现在分词形式，更加强调完成的结果在持续进行中，和1920时间点不符合；
had reduced 和 reduced：过去完成时两种意思：动作发生在过去的过去，或者过去的动作造成的影响；had reduced这个动作发生在block同一时期，句子中写by 1920，过度捕捞的结果已经显现：鱼群减少；
a lower amount / an amount lower表达的效果和less相同，表达形式名词化之后，不够简练
请登录或注册以提交给你的回答
