The number of jobless adults in China rural areas is larger than that of____________.

A．Do extra work if necessary.
B．Change the spark plugs only.
C．Clean the spark plugs only.
D．Charge her more than ￡ 10 if necessary.

A．Children reared under average conditions possess average intelligence.
B．Lack of opportunity prevents the growth of intelligence.
C．An individual’s intelligence is determined chiefly by his environment.
D．Changes of environment produce changes in the brain structure.