《高速铁路有砟轨道线路维修规则》规定，调节器定期观测并分析基本轨伸缩量、焊缝位置与气温关系，发现伸缩故障应及时消除。
参考答案：对
---Have you heard about Volunteer?
---Sure, A volunteer is someone _________ is willing to offer help without being paid..
A．who
B．what
C．where
D．which
中国民间为什么要吃腊八粥？（）
