it is normal for parrots to talk, Einstein, a small bird, is unusual in that whenever she

it is normal for parrots to talk, Einstein, a small bird, is unusual in that whenever she hears a new word or sound, she repeats it over and over until she masters it.
A. As
B. When
C. While　　
D. Since

A. AsB. WhenC. While　　D. Since解析：选C。考查状语从句。句意: 尽管鹦鹉说话是正常的, Einstein, 一只小鸟, 是非同寻常的, 因为每当她听见一个新单词或者声音的时候, 她总是重复说直到掌握。while尽管; as因为; when当……的时候; since既然。

和我的回答一样，看来我也对了