And Presidents Barack Obama and Felipe Calderon have pledged cooperation on a wide range of issues - especially border security aimed at battling drug and gun trafficking, and the flow of illegal immigrants into the United States.
VOA: standard.2010.05.17
You turn on your lamp, it happens pretty fast because current can flow very quickly through wire or through a charged - a solution of ions.
你打开灯 灯马上就亮了,电流可以迅速通过,电线或者带电荷的--电解质的溶液
You turn on your lamp, it happens pretty fast because current can flow very quickly through wire or through a charged - a solution of ions.
你打开灯 灯马上就亮了,电流可以迅速通过,电线或者带电荷的--电解质的溶液
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