[单项选择]Agriculture was a step in human progress ______ which subsequently there was not anything comparable until our own machine age.
A. in
B. for
C. to
D. from

[单项选择]Agriculture was a step in human progress ______ which subsequently there was not anything comparable until our own machine age.
A. in
B. for
C. to
D. from

[单项选择]Agriculture was a step in human progress （） which subsepuently was not anything comparable until our own machine age.
A. in
B. for
C. to
D. from

[单项选择]Agriculture was a step in human progress ______ subsequently there was nothing comparable until our own machine age.
A. to which
B. signal
C. from which
D. in which

[单项选择]Agriculture was a step in human progress _________ which subsequently there was not anything comparable until our own machine age.
A. in
B. for
C. to
D. from

[单项选择]Human behavior is mostly a product of learning, whereas the behavior of an animal depends mainly on ______.
A. consciousness
B. impulse
C. instinct
D. response

[单项选择]

The agriculture revolution in the nineteenth century involved two things: the invention of labor-saving machinery and the development of scientific agriculture. Labor-saving machinery naturally appeared first where labor was scarce. "In Europe", said Thomas Jefferson, "the object is to make the most of their land, labor being sufficient; here it is to make the most of our labor, land being abundant". It was in America, therefore, that the great advances in nineteenth-century agricultural machinery first came. At the opening of the century, with the exception of a crude (粗糙的) plow, farmers could have carried practically all of the existing agricultural tools on their backs. By 1860, most of the machinery in use today had been designed in an early form. The most important of the early inventions was the iron plow. As early as 1890 Charles New bolt of New Jersey had been working on the idea of a cast-iron plow and spent his entire fortune in introdu
A. Europe
B. America
C. New Jersey
D. Indiana