It's dangerous to let the children who are _____ go swimming in the river. 

A. too young to    B. so young    C. not old enough to    D. so old

It's dangerous to let the children who are _____ go swimming in the river.

1. A.
   too young to
2. B.
   so young
3. C.
   not old enough to
4. D.
   so old

（2010·湖南衡陽八中高三上第二次月考）      32. It's dangerous to let the children who are _____ go swimming in the river. 

A. too young to            B. so young   

C. not old enough to    D. so old