- 问题详情:WASHINGTON,March13—When17-year-oldMaryMastermansetouttobuildaspectrograph(摄谱仪),sheknewitwouldbenoeasytask.Thedevice,aninstrumentusedtoidentifycharacteristicsofdifferentkindsofmolecules,cancostthousandsofdollars,andMarywasbuildingonabudget....
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