地球的磁层既具有保护的功能,却又极其危险。The earth's magnetosphere is at once protective and dangerous.在磁层顶合成3D磁结构的聚类观测.Cluster observations of complex 3 D magnetic structures at the magnetopause.本文解出了三维磁层顶的Chapman-Ferraro模型.Chapman - ...
He may have been to some of those places.那些地方他也许去过一些。Those who have been to Dalian all say it's beautiful.凡是去过大连的人都说大连很美.I have been to see John.我去看过约翰了....