为了改善孔壁粗糙度，采用滚压工艺光整加工时，宜将滚压头在孔内多次滚压。( )
参考答案：错
It was so dark outside that the little child ________ go out by himself.
A．dare not to
B．dared
C．dares
D．didn’t dare to
客货运输票据属有价证券，是铁路运输企业核算运输收入的原始凭证。（部竞赛题）
