扫描二维码，直接登录
题库 / OG2017V-SC-226
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.
that have blocked shad migrations up their spawning streams had reduced landings to less
that blocked shad from migrating up their spawning streams had reduced landings to less
that blocked shad from migrating up their spawning streams reduced landings to a lower amount
having blocked shad from migrating up their spawning streams reduced landings to less
having blocked shad migrations up their spawning streams had reduced landings to an amount lower
A选项：have blocked shad现在完成时态修饰发生在1920年之前的事情有问题；migrations up...应该用V;
B选项：时态和动词使用均无问题；
C选项：时态过去时没有过去完成时好；同时a lower amount 表达wordy,可以直接less than...
D选项：have的现在分词前面应该有逗号；过去完成时会使表达效果更好；
E选项：have的现在分词前面应该有逗号；migrations，to an amount lower错误同上；
登录 或 注册 后可以参加讨论