After visiting Harbin, most of the foreign friends said they would never forget the time ________ they had spent.
A．that B．what
C．when D．at which
Eleven people got killed in the accident, ________ the identities haven't been available.
A．whose B．of whom
C．to whom D．with whom
It's said to be a case of murder ________ the children were used by adults.
A．when B．where
C．which D．that
Naturally a smile ________ the eyes participate is extremely communicative.
A．to which B．in which
C．at which D．with which
With hundreds of attractions, Beijing is a city ________ makes a lasting impression on its visitors.
A．which B．where
C．what D．when
Just use this room for the time being, and we'll offer you a larger one ________ it becomes available.
A．as soon as B．unless
C．as far as D．until
