A．It is made up of the nerves near muscles．
B．The nerve message knows how to control human's motion．
C．It is produced by our muscles．
D．It is helpful to coordinate the limbs and motion．

A．Because they got unemployed in the Industrial Revolution．
B．Because they could get land to farm there．
C．Because they suffered from political refuge．
D．Because they suffered from famine．

A．The newcomers brought different cultures．
B．They couldn't tame the newcomers．
C．The newcomers would stay together with them．
D．The newcomers would disturb the employment market．