单项选择题
A.a safety line attached to a man working over the side B.used to measure water depth C.used to slow the headway of a barge D.used to measure the overhead height of a bridge
（）is the course to reach you?A.WhatB.HowC.WhichD.When
单项选择题（）is the course to reach you?
A.What B.How C.Which D.When
（）is the chain?A.HowB.WhatC.WhyD.How about
单项选择题（）is the chain?
A.How B.What C.Why D.How about
