问题
选择题
---Have you returned the book to the library ____? ---Yes, I have ____ returned it.
A．yet, yet
B．already, already
C．already, yet
D．yet, already
答案
D
yet和already都表示 “已经”之意，通常用于完成时态。yet 用于问句或否定句，位于句尾；而 already 用在肯定句里，位于句中，即be动词或助动词之后，行为动词之前。故本题选D。