There is no that 100 years ago animal testing was cruel, but today animals in experiments are very well taken care of.
A. point
B. wonder
C. use
D. doubt
网友回答
A. point
B. wonder
C. use
(答案→)D. doubt
解析：考查固定句型，There is no doubt that…意思“毫无疑问…”，句子意思“毫无疑问100年前动物测试很残酷，但是今天做实验的动物得到很好地照顾”，所以选D