用接触焊焊接的钢轨焊缝容易产生的缺陷主要是:()、冷焊和过烧。
参考答案:灰斑
_______ the Chinese athletes will make a new breakthrough at the 2012 London Olympic Games
becomes the focus of attention.[ ]
A. That
B. Whether
C. When
D. What
隧道应进行监控量测设计,其费用应列入()。