实验课上，小柯在低倍镜下看清某种细胞结构后，将显微镜轻移到小妍面前给她看，而小妍看到的却是较暗的视野，她首先应操作的是（ ） A．目镜
Our sports meeting has been ____ till next Monday because of the bad weather.A．put onB．put upC．put offD．put down
________ I heard someone calling for help，I rushed out. A．Immediately B．At the time C．For the first time D．Immediate
下列说法：①若a、b互为相反数，则a+b=0；②若a+b=0，则a、b互为相反数；③若a、b互为相反数，则；④若则a、b互为相反数．其中正确的结论有（ ）
．“三角贸易”是15到19世纪西方殖民掠夺的一个重要方式。读右图《三角贸易示意图》，其中航程B贩运的主要是
根据下列表格的对应值，判断方程ax2＋bx＋c＝0(a≠0，a，b，c为常数)一个解的范围是( ) x3.233.243.253.26 ax2＋bx＋c－0.06－0.020.030.09 A．3＜x＜3.23
苏丹红是很多国家禁止用于食品生产的合成色素。结构简式如下图：关于苏丹红说法错误的是（ ） A．分子中含一个苯环和一个萘环 B．属于芳香烃
It was Monday. Mrs Smith's dog was hungry, but there was not any meat in the house. Considering that there was no better way. Mrs Smith took a piece of paper, and wrote the following words on it:“Gi
