Children are to meet with setbacks as they grow up so their parents don’t have to worry

问题补充：

Children are to meet with setbacks as they grow up, so their parents don’t have to worry about it．

A. possible

B. due

C. necessary

D. bound

答案：

A. possible

B. due

C. necessary

(答案→)D. bound

解析：句意：孩子们在长大的过程中，一定会碰到一些挫折，所以他们的父母不要担心。be bound to 注定，一定要，be possible to 可能的 be due to由于 be necessary to是必要的，根据题意，故选D。