A:人口自由流动
B:土地兼并
C:稳固自然经济
D:减轻地租
读图,完成以下问题。
如图,△ABC为钝角三角形,将△ABC绕点A按逆时针方向旋转120°得到△AB′C′,连接BB′,若AC′∥BB′,则∠CAB′的度数为( )
Helen is going to work in an old people's home to help ________ the old people.