已知定义在R上的函数时，单调递增，当时，单调递减. （1）求b的取值范围； （2）设的三个根分别为
On Sundays there were a lot of children playing in the park, _______ parents were seated together joking. A. their B. whose C. which
下列哪一战役为解放大西南奠定了基础？ A．渡江战役 B．衡阳保卫战 C．衡宝战役 D．湘西会战
“May I take your order now?” “We’d like three black _______ and two green _______.” A. coffee, cups of teas B. coffees, teas C. cups of coffee, tea D. cup of coffees, teas
下列说法不正确的是( )A.任何化学反应都伴随有能量变化B.化学反应中的能量变化都表现为热量的变化C.反应物的总能量高于生成物的总能量时，发
He _____ to join the art club, because he can ______ very well. A want, draw B wants, draw C wants, sing D want, to sing
【3分】下图是一套实验室制取某气体并测量产生的该气体体积的装置，符合此实验要求的反应物是下列各组中的( ) A.浓盐
