单项选择题
A．Migration exerts a great impact on population change. B．Migration contributes to mankind's progress. C．Migration brings about desirable and undesirable effects. D．Migration may not be accompanied by human conflicts.
A．well deserved the punishment. B．invested in a senseless way at the time. C．were unduly punished in the crisis. D．had bad relationships between government and business.
A．due. B．remote. C．imaginative. D．unpredictable.