No driver is allowed to drive his car into this area _______ he

No driver is allowed to drive his car into this area _______ he has a special pass.
A、unless
B、if
C、if only
D、except
【正确答案】：A
【题目解析】：unless 除非，if 如果， if only 要是……， except 除了句意：司机是不允许开车进入这个区域的，_____他有特别通行证。A符合题意，除非他有特别通行证。