their final medical check, the astronauts boarded their spacecraft.
A. Received
B. Being received
C. To receive
D. Having received
网友回答
A. Received
B. Being received
C. To receive
(答案→)D. Having received
解析：考查非谓语动词。接受体格检查再等上航天飞机之前，且主语与动作之间是主动关系，故需要用现在分词的完成式。