【简答题】将一块正六边形硬纸片(如图),做成一个底面仍为正六边形且高相等的无盖纸盒(侧面均垂直于底面,见下图),需在每一个顶点处剪去一个四边形,例如图中的四边形AGA′H,那么∠GA′H的大小是( ) 度。
【单选题】今年7月底之前,七里河餐饮业所有使用高污染燃料的炉灶将全部改用清洁能源。下列不属于清洁能源的是
【单选题】She lays great _______ on proper behavior.
【简答题】有四种边长都相等的正三角形、正方形、正五边形、正六边形瓷砖,如果任意用其中两种瓷砖组合密铺地面,在不切割的情况下,能镶嵌成平面图案的概率是______.
【单选题】She ________ great importance ________ regular exercise. [ ]
【单选题】The professor implies that the relationship between mosquitoes and humans has characteristics of which types of symbiosis?
A.
Amensalism and commensalism.
B.
Parasitism and commensalism.
C.
Competition and mutualism.
D.
Competition and parasitism.