He collected information on 1,000 people, whose IQ when they were ten years old.
A. is tested
B. has tested
C. would test
D. had been tested
网友回答
A. is tested
B. has tested
C. would test
(答案→)D. had been tested
解析：考查时态。根据句意可知这1000人被测量IQ的动作发生在他收集信息collect information该动作之前，故选择过去的过去，即过去完成时。