问题详情

Throughout history gold has been important in human society. Men【36】for it. People have suffered great hardships searching【37】it. They have gone to the distant corners of the earth【38】to find a great fortune. A kind of madness【39】people when they think about gold.
For centuries, starting in ancient times, gold was most【40】found mixed with sand in streams.
This is one reason【41】even early humans used it. They could find it without using tools to dig it【42】the ground. It was also valuable to【43】because it is very soft. It is one of the softest 【44】and also one of the heaviest. It is easy to work into jewelry and【45】decorations. It is beautiful and lasts forever.
(36)
A．have died
B．have been dying
C．have been died
D．are dying请帮忙给出正确答案和分析，谢谢！