按桩的承载形状分为()
A、预制桩
B、摩擦型桩
C、端承型桩
D、混凝土灌注桩
参考答案:B, C
通常工作在UDP协议之上的应用是()。
A.浏览网页
B.Telnet远程登录
C.VoIP
D.发送邮件
He got up late and hurried to his office, _________the breakfast untouched.[ ]
A. left
B. to leave
C. leaving
D. having left