— Are you a visitor here?  

— That's right. I     ___ round the world and now my dream of coming to China      ___ true.[ ]

A. have traveled; has come

B. travel; has been come

C. am traveling; has come               

D. have traveled; has been come

钳型表在测试时，正确的是（）

A.钳口需闭合紧密

B.由于是间接测试，所以无须考虑安全的问题

C.钳型表的测试原理是基尔霍夫定律

D.以上都不正确