神马品牌网治疗肾结石中药配方:一道英语题。
来源：百度文库 编辑：神马品牌网 时间：2024/05/13 11:42:30
It's useful to do sth还是It's useful doing sth.
It is useful to do sth.
It is no use doing sth.
应为It's useful to do sth
一般为It's+形容词(如：helpful thankful )to do sth
t's useful to do sth
恩,就是It is useful to do sth.
前者！