1 . My father retired in 2008, _____ he has been devoting his time to gardening.

A．at which	B．since when
C．when	D．after that

2 . At the request of some English learners, he has published a lot of books, one of _______ is about English idioms.

A．whom

B．those

C．them

D．which

3 . In all his life, Dickens wrote a large number of excellent novels in the 19^th century, _____ some are still popular nowadays.

A．whose	B．of that
C．in which	D．of which