A．Europe was changing more quickly than the United States.
B．Europe had greater need of farm machinery than the United States.
C．The United States was finally running out of good farmland.
D．There was a shortage of workers on the United States farms.

A．If we think well of ourselves, we will act with confidence.
B．Shy people have trouble accepting compliments.
C．People are shy because they care about their appearance and actions.
D．Shy people are easily hurt by criticism.