您好,I like tea there isn't milk in it. 有语法错误,因为这个句子有两个主语,I 和 there,要改成定语从句,可以考虑:
1)I like tea that has no milk in it.(that 替代从句主语)
2)I like tea which has no milk in it.(which 替代从句主语)
3)I like tea where there isn't any milk.(where 替代 in it)
4)I like tea in which there isn't any milk.(in which 替代 in it)
不用定语从句更简单扼要的用法是使用 without:
1)I like tea without milk (in it).