设 n 维向量组 α 1 , α 2 , ⋯ , α s ,若任一维向量都可由这个向量组线性表出,必须有 。
Goods are carried by several of transport--on road or rail, by sea or air.
A campus emergency ______ occur at any time of the day or night, weekend, or holiday, with little or no warning.
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