问题详情

What did eighteenth-century astronomers have in common with astronomers today？

A．They could not explain everything they detected with their instruments.

B．They knew the correct distances of objects they could not identify.

C．Their instruments were not powerful enough to detect spiral nebulae.

D．They argued over the natural brightness of variable stars.

此题为多项选择题。请帮忙给出正确答案和分析，谢谢！