A-A+

This is an illness that can result in total bl

2022-08-06 13:44:22 问答库阅读 179 次

问题详情

This is an illness that can result in total blindness _________ left untreated.
A．after
B．if
C．since
D．unless

正确答案：B
解析：真实条件句的缩略式。完整的真实条件句是“if the illness is left untreated”。请参阅第一套模拟题注释74。