电炉冶炼含Ti的Ni-Cr不锈钢时，要求Ti/C比，其目的是（）。
A．提高强度
B．防止裂纹
C．防止晶间腐蚀
参考答案：C
从A、B、C、D四个选项中选出与所给句子划线部分意思相同或相近并能替代的的那一项。
— Who went to school early last term?
— Meimei used to be the first one. [ ]
A. got used to being
B. was used to being
C. was often
D. was used
使成立的f（x）为（）。
A．A
B．B
C．C
D．D
成立的f（x）为（）。