They ______ in the park when it started to rain. A. walked B. were walking C. walk D. are walkingĐoạn văn32/41TASK 2. Choose the best option to complete each sentence. Circle A, B, or C.They ______ in the park when it started to rain. walkedwere walkingwalkare walkingGiải thíchĐáp án đúng là B