举重，每次试举成功后，杠铃重量必须至少增加（）。
参考答案：1千克
We ______ the difficulty together, but why didn't you tell me?
A．should face
B．might face
C．could have faced
D．must have faced
与十进制数291等值的十六进制数为
A．123
B．213
C．231
D．132
