Question

Don’t let the child who is ________ go to school． 

A．so young as to

B．not old enough to

C．not old enough

D．too young to

Answer 1

C

这题考查定语从句：who is old enough是定语从句，修饰the child，而谓语let后面接宾语+省略to的不定式。选C。句意是：别让年龄不够的孩子上学。