某产品杂质含量技术指标是≤0.03%,测定值为0.0025%(+),则报出结果为()
A.0.0025%
B.0.003%
C.0.002%
D.0
参考答案:B
It was not easy to let all the children ________ into the classroom in a short time. [ ]
A. run
B. to run
C. running
D. ran
交—直流电传动装置主要由()、整流装置和()等组成。