若向量\( \overrightarrow{a}=(2,0)\)，\( \overrightarrow{b}=(1,1)\)，则下列结论正确的是\((\) \()\)
A. \( \overrightarrow{a}⋅ \overrightarrow{b}=1\)
B. \( \overrightarrow{|a|}= \overrightarrow{|b|}\) C. \(( \overrightarrow{a}- \overrightarrow{b})⊥ \overrightarrow{b}\) D. \( \overrightarrow{a}/\!/ \overrightarrow{b}\)
