优题课 - 聚名师,上好课(www.youtike.com)
  首页 / 试题 / 高中英语 / 试题详细
  • 科目:英语
  • 题型:单选题
  • 难度:中等
  • 人气:567

It has been proved ____ several new kinds of medicine____ a positive effect on the cure of H7N9.

A.which,has B.if, has
C.that, have D.what, have
登录免费查看答案和解析

Ithasbeenprovedseveralnewkinds