D
本句的意思是：“即使研究有了新的发展，只有一小部分的试验可以不用动物”。因此答案为D。variety和plenty分别表示“多样”和“大量的”，意思不合适。amount后只能接不可数名词，而test是可数名词。
This is the first time that a woman has been ________ to the post.
Wetrustyouwilldoyourbesttohavethismatter__________rightaway.()
Which of the following techniques is NOT used in the Grammar-Translation Method?________
PleasemakesurethatthestipulationsintheL/Care______exactaccordanee___thetermsoftheSalesContract.
ltisnecessary___youtocomplywithourshippinginstructions.
