8.18×104精确到______位;5.4万精确到______位.
8.18×104精确到百位;5.4万精确到千位.
There ________ some CDs on the shelf. [ ]
A. is
B. are
C. have
D. has
抛磨圆钻台面及主要刻面多采用()方法。
A.多面抛磨
B.交叉抛磨
C.按序抛磨
D.交棱抛磨