Scientists have been unable to ________ their findings with recent increases in radioactivity levels.

A．Language is as useful as music.
B．Painting is the best of all in lifting one's spirits.
C．To see human's bright side is a game of chance.
D．Not everyone is given the chance of a good future.

A．Physiological changes will for sure betray a liar.
B．The bigger a lie is, the stronger the strain will be.
C．The degree of the strain depends on the purpose of lying.
D．A well-trained person can tell lies without being detected.