题目

计算：（1）﹣（）﹣1+（π﹣3）0；（2）（x+2y）2﹣2x（3x+2y）+（x+y）（x﹣y）． 答案：【答案】(1) ;(2) 【解析】（1）本题涉及零指数幂、负整数指数幂、二次根式化简3个考点. 在计算时, 需要针对每个考点分别进行计算, 然后根据实数的运算法则求得计算结果. (2)利用完全平方公式及平方差公式与平方差公式化简, 后合并同类项可得答案.解：（1）原式==． （2）原式= =． He was the one of the graduate students ________ to do the research work in the lab． [　　] A．to whom it was their responsibility B．whose responsibility there was C．whose responsibility was D．of whom with the responsibility