Farm workers ______ only a small section of the population.

A.unemployment

B.lack

C.market

D.vocation

A.In 1942

B.In 1962

C.In 1968

D.In 1970

A.joining in different unions

B.carrying out nonviolent acts

C.becoming a migrant farm worker

D.passing laws to permit workers to build unions

A.the aging of immigrant farm workers

B.the rising number of illegal immigrants

C.the high mobility of crop workers

D.the lack of experienced laborers

A.a rise in work efficiency

B.a redaction in average income

C.a decline in grain production

D.a shortage of farm workers

A.a rise in work efficiency

B.a shortage of farm workers

C.a decline in grain production

D.a reduction in average income

A.patterns of family behavior

B.women who are initiating social change in a small region in Texas

C.migrant agricultural workers

D.how migrant farm workers lived in the past

A large population in an underdeveloped country may lead to______.

A．a rise in work efficiency

B．a shortage of farm workers

C．a decline in grain production

D．a reduction in average income

A.To attract younger laborers to farm work.

B.To get native U.S. workers back farming

C.To use more robots to grow high-value crops

D.To strengthen financial support for farmers.

From the passage we can find out that the author mainly studies ______.

A．patterns of family behavior

B．women who are initiating social change in a small region in Texas

C．migrant agricultural workers

D．how migrant farm workers lived in the past