A:
B:
C:
D:
完形填空。
Today is Saturday. It's 1. Jack and Kitty go to a park in the country side. The wind is 2 gently. The clouds are moving slowly in the 3. Some birds are singing in the trees. They are flying a kite 4. The kite flies 5 the tree. Suddenly(忽然),The wind 6 strong. The clouds are moving quickly. The strong wind blows their kite away. Jack and Kitty go home quickly.
已知不等式组y-1≥0x+y-4≤0y-1≤kx-1(k>0)表示的平面区域为D,若∀(x,y)∈D,yx2≤1恒成立,则实数k的取值范围是____
北京培育出优质甘蓝品种,叶球最大的只有3.5kg,当引种到拉萨后,由于昼夜温差大,日照时间长,叶球可重达7kg左右,但再引种回北京后,叶球又只有3.5kg,从甘蓝引种过程看出( )
图1、图2是两张形状、大小完全相同的方格纸,方格纸中的每个小正方形的边长均为1,每个小正方形的顶点叫做格点.
(1)在图1中画出等腰直角三角形MON,使点N在格点上,且∠MON=90°;
(2)在图2中以格点为顶点画一个正方形ABCD,使正方形ABCD面积等于(1)中等腰直角三角形MON面积的4倍,并将正方形ABCD分割成以格点为顶点的四个全等的直角三角形和一个正方形,且正方形ABCD面积没有剩余(画出一种即可).
香港、澳门特别行政区位于美丽富饶的珠江三角洲,这里气候湿热,四季常青;经济繁荣,风景优美。根据所学知识,回答下列各题。