问题补充：
The police recommended parents their children under 12 to ride to school for safety. allow
A. not allow
B. do not allow
C. mustn’t allow
D. couldn’t
答案：
(答案→)A. not allow
B. do not allow
C. mustn’t allow
D. couldn’t
解析：本题考查虚拟语气。recommended后面是一个省略that的宾语从句。而recommend后的宾语从句应用(should)+do,故本题应是：…parents should not allow their children…,should省略了，故选答案：A.
