问题补充：
What worried the woman most was to visit her sick son in hospital.
A. not allowing
B. not being allowed
C. not allowed
D. having not being allowed
答案：
A. not allowing
(答案→)B. not being allowed
C. not allowed
D. having not being allowed
解析： 考查非谓语动词作表语。因为the woman和allow之间是动宾关系，所以要用doing的被动式。所以选B.
