二级中误差公式为()。
A.0.02+0.0006S
B.0.01+0.0003S
C.0.02+0.001S
D.0.04+0.003S
参考答案:C
I was trying to pick up my hat that __________ off in the wind, but failed at last.
A. had been blown . is blown C. blown D. it had been blown
________from the outside by the flood for months, the villagers are short of everything.[ ]
A. Cut away
B. Cut down
C. Cut off
D. Cut out