ExercisesContentsDownloadsUNIT 5: PAST CONTINUOUS AND PAST SIMPLEQuestion 1 / 20请完成全部题目,最后查看答案与解析GRAMMAR · A2 · TYPE YOUR ANSWERExercise 1 · Exercise 1Type the missing word or phrase.I _____ while I _____ down the stairs.输入单词、短语或完整答案;多空答案用 / 分隔保存并进入下一题 →