等离子弧会产生高强度、高频率的噪声,噪声能量集中在()范围内。
A.2000~8000Hz
B.200~800Hz
C.20~80Hz
D.2~8Hz
参考答案:A
The kid is crying, for he ______ jump over the ditch on his own.
A.dares not to
B.dare not to
C.doesn’t dare to
D.dares not
过错推定