题目内容

When ____ comes to research into heart disease and the effects on the body,we do not have adequate substitutes for the use of animals.

A. that  B. it   C. what      D. this

 

练习册系列答案
相关题目

违法和不良信息举报电话:027-86699610 举报邮箱:58377363@163.com

精英家教网