根据选煤厂机电设备完好标准规定，重介旋流器锥部排砂管磨损不大于原直径的（）
A.8%
B.10%
C.11%
D.12%
参考答案：A
My sister can ______.[ ]
A. sing
B. sings
C. to sing
D. singing
In the International Code of Signals，the code signal meaning I require immediate assistance is（）.
A.AE
B.CB
C.DX
D.CP
