题目

先化简，再求值：，其中. 答案：解:原式= (2分)          = (2分) 当=时(1分),原式=.(1分)Tom and Jack are both very clever. ________, Tom is _______ Jack. A．All in all, as a clever boy as                B．In other words, as clever a boy as C．That is to say, as a clever boy as             D．In word, as clever a boy as