问题
单项选择题
All staff members are reminded that you should not use the executive restroom ______ you have written authorization to do so.
A. for
B. unless
C. without
D. although
答案
参考答案：B
解析：横线前后都是完整结构，故横线处应填入连词。先排除介词(C)without，将其他备选答案一一代入后分析金句。you have written authorization to do so(有书面批准)是use the executive restroom(使用主管休息室)的条件，故答案是(B)unless。
(-1≤x≤1)与x轴所围区域的面积S=______．
