Help
End Section Review
End Exam
Answer Edit Confirmation
课程
活动
资料
反馈
题目内容
The science of astronomy was begun by amateurs and today remains dependent on their contributions, which are incisive by virtue of being by the a priori assumptions that often vitiate the work of professional research scientists.
学员19vkra
学员17xlam
学员19zowr
学员17bpfs
学员17vpfv