A． They describe how habits affect our behaviour.
B． They are on issues facing office workers today.
C． They investigate the functions of the brain.
D． They reveal how memories are developed.

A． It enabled the researchers to track participants' memories.
B． It provided exciting images of famous people and places.
C． It stimulated volunteers' memories of a given moment.
D． It caused subjects to forget their memories for a while.

A． Because they could bring a special feeling to the participants.
B． Because they could produce a desirable experimental result.
C． Because they could stimulate participants' bold imagination.
D． Because they could evoke sweet memories in people's mind.