端头支护时,应注意什么?
参考答案:
端头支护前,必须在已有的完好支护下,用长把工具敲帮问顶,摘除悬矸危岩和松动的煤帮;窜料、上网维护顶板时,必须停机闭锁,观察好顶板、煤帮。
Though it is 30 years _____ we last met, I still remember the scene ______ we got separated on a
rainy day. [ ]
A. before; where
B. before; which
C. since; when
D. since; where
张永庆开了一个用来给创业提供咨询的会馆。