英语 八年级 词汇题 较难

含情态动词的被动语态 — 英语词汇题

沪教版·英语(初中) Unit 5 Saving animals in danger AI 三重审校通过

题目
Complete the sentence with the correct form of the words in brackets: To keep the rescued bears safe, they must not ______ (单独留下:leave alone) during the journey.