已知x,y满足,如果目标函数z=的取值范围为[0,2),则实数m的取值范围为( ) A.[0,] B.(﹣∞,] C.(﹣∞,) D.(﹣
图为关节的剖面示意图,请据图回答。 (l)骨与骨之间接触的部位[ ] 。 (2)患关节炎时,可能引起积
衣藻、蓝藻、黑藻全部( ) A.是原核生物 B.含有叶绿体 C.是自养生物 D.含有中心体
在长期放着煤的墙角处,地面和墙角壁面相当厚的一层染上了黑色,这说明( )A.分子是在不停地运动着 B.煤是由大量分子组成的C.分子
In order to prevent the disease ___________ to other districts, the authorized organization killed thousands and thousands of cows. A. extending B. spreading C. expandi
地名变更往往同当时的政治背景相关,苏联历史上曾经发生下列地名变更:( )①彼得格勒→列宁格勒 ②沙皇村→儿童村③
Many people find it difficult to do any activity for pure pleasure. I'm here to tell you about one of my favorite pleasures. It doesn't cost a thing and takes very little time. Best of all,you ca
Every morning Mr. Smith takes a ______ to his office. A.20 minutes’ walk B.20 minute’s walk C.20-minutes walk D.20-minute walk