英语 高三 选择题 较难

定语从句介绍发明与技术 — 英语选择题

沪教版·英语(高中) Unit 4 Technology AI 三重审校通过

题目
Choose the best relative word(s) to complete the sentence: The satellite-based warning system, ___ emergency teams receive storm alerts, was designed to keep the signal working even when mobile networks fail. A. through which B. through that C. where D. whose