埋弧焊熔合比最小，电弧搅拌作用强烈，形成的过渡层比较均匀，是异种钢焊接应用极为广泛的焊接方法。( )
参考答案：错
The party last night was _____ success. We sang and danced until it came to _____ end at twelve. [ ]
A. a; an
B. a; the
C. the; an
D. 不填; an
通信距离与哪五个因素有关？
