持有两张以上主卡，该如何还款？
参考答案：
如持卡人同时拥有多张主卡，还款时请分别以人民币和美元，按主卡卡号分别还款。
Many people think it necessary for people who are out of work ______so that they can acquire one
or more basic skills for survival in modern society. [ ]
A. be reeducated
B. being reeducated
C. to be reeducated
D. reeducated
高浓度的CO2引起气孔张开；而低浓度的CO2则引起气孔关闭。
______so that they can acquire one 