单根粗钢筋作预应力筋用帮条锚具时,帮条焊应在预应力钢筋冷拉后焊接。( )
参考答案:错
To be honest, I didn’t______ him at first sight. About an hour later, I remembered him.
A.realize
B.understand
C.see
D.recognize
已知:42=a4,272=3b。化简求值:(3a-2b)2-(a-3b)(2a+b)+(3a+b)(3a-b)。