英语 高三 填空题 标准 ★ 精品

非谓语动词作定语和状语 — 英语填空题

外研社版·英语(高中) Unit 5 Learning from nature AI 三重审校通过

题目
用所给动词的适当非谓语形式填空(每空一词):Scientists, ______ (observe) how lotus leaves stay dry, have developed self-cleaning materials ______ (base) on the same principle, ______ (allow) buildings to stay clean without chemicals.