渗碳件淬火温度过低将导致心部铁素体偏高。
参考答案：对
He had studied hard, he would have been able to pass the exam.
A. He had studied harder B. If only he studied moreC. Had he studied harder D. When he studied more
某同学在实验室用氯化钠固体和蒸馏水配制100g溶质质量分数为15%的氯化钠溶液时，涉及以下操作：①称量，②溶解，③计算，④装入试剂瓶贴好标签．
配制上述溶液的操作顺序是______（填序号）
