That was a very busy street that I was never allowed to cross accompanied by an adult.A. w

问题补充：

That was a very busy street that I was never allowed to cross accompanied by an adult.

A. when

B. if

C. unless

D. where

答案：

A. when

B. if

(答案→)C. unless

D. where

解析：本题考查连词的用法。when当……时候；if如果；unless除非；where在……地方。句意：那是一条非常繁忙的大街，除非有成年人陪同我是不容许穿越的。