问题补充：
Only when your identity has been checked .
A. you are allowed to
B. you will be allowed in
C. will you allow in
D. will you be allowed in
答案：
A. you are allowed to
B. you will be allowed in
C. will you allow in
(答案→)D. will you be allowed in
解析：考查倒装句。Only放在句首，且强调状语的时候，使用部分倒装的形式，本题only放在句首，强调的是时间状语从句when your identity has been checked故使用部分倒装的形式。根据句意说明使用被动的形式。句意：只有当你的身份被检查以后，你才被允许进入。故D正确。
