HXD3型电力机车制动盘允许存在沿径向、周向热裂纹,从摩擦面内外边缘开始的长度不超过()mm;其余热裂纹长度不超过65mm。
A.55
B.60
C.65
参考答案:B
This _____ my sister and those _____ my parents. [ ]
A. is; is
B. are; are
C. are; is
D. is; are
表达式a+=a-=a=9的值是
A.9
B._9
C.18
D.0