Questions 18-21 are based on the following dialogue between a doctor and his patient.

In what tone does the man talk to the woman

A．An increase in free parks is two-edged.
B．There were 99 free parks in Shanghai before April 1,2005.
C．Shanghai spent more than 3 per cent of its GDP for the "National Garden City" award in 2004.
D．Shanghai’s goal is to increase its green area to more than 204 million square meters.

A．It is the second time he has been in China.
B．He likes China very much.
C．He used to be a teacher in China.
D．He is a young man.