When asked why he went there, he said he was sent there for a space flight.
A. training
B. being trained
C. to have trained
D. to be trained
网友回答
A. training
B. being trained
C. to have trained
D. to be trained
解析：由于“他”与“训练”之间为被动关系，故可排除A和C。另外，由于被训练进行航空飞行是他被派往那儿的目的，所以宜用不定式，故选D。