she was___(购物) when she saw the accident?横线中应该添?最好是讲解一下 谢谢 要快哦

问题描述:

she was___(购物) when she saw the accident?
横线中应该添?
最好是讲解一下 谢谢 要快哦

shopping
be doing when.的句式,意味正在做某事,这时怎样