These kids are quick at learning. We had better have them in a new way.A. having been tra

问题补充：

These kids are quick at learning. We had better have them in a new way.

A. having been trained

B. training

C. being trained

D. trained

答案：

A. having been trained

B. training

C. being trained

(答案→)D. trained

解析：考察非谓语动词。句意：这些孩子们学的很快。我们最好用一种新的方法训练他们。使役动词后接过去分词表示把某事做了。故选D。