Dung beetles ______ an integral part of the successful management of diary farms

游客2023-11-09  24

问题 Dung beetles ______ an integral part of the successful management of diary farms in Australia over the past few decades.

选项 A、has become
B、have become
C、became
D、had become

答案 B

解析 时态题。在由until(till,up to)now,up to the present,so far,in (for,over,during)the past(last,recent)few(several,two...)months(days...)等构成的短语作状语的句子中常用现在完成时。主语dung beetles复数形式,故B正确。
转载请注明原文地址:https://tihaiku.com/zcyy/3172618.html
最新回复(0)