英语 九年级 选择题 较难

现在完成时 — 英语选择题

人教版·英语(初中) Unit 13 We're trying to save the earth! AI 三重审校通过

题目
Over the past five years, factory waste ___ the small lake, so fewer fish live there now. A. have polluted B. polluted C. is polluting D. has polluted