某校初三化学兴趣小组对惠州西湖水质的状况进行了相关的研究调查.
Tomorrow we will go to Hainan. It's warm there. We will have a special Chinese New Year's Day. Now let's get ready! We need three tickets from Shijiazhuang to Hainan. We don't need winter clothes. I want a beautiful dress. My parents take some T-shirts and shorts. We need to take milk, cakes and fruit. We need three hats. The sun is very hot there. We don't want to turn black. That's all done.
① ② ③ ④
⑤ ⑥ ⑦ ⑧
⑨ ⑩ ⑪ ⑫
____
在横线上写一句话,使之与前后文构成结构一致、内容相关的排比句。
欣赏是一种学习,一种感悟,一种特别的收获。欣赏一封短短的家书,会让你想起故乡的亲切与温馨;____,____;欣赏一束淡淡的康乃馨,会让你享受生命的清雅和悠扬……
定义:若抛物线的顶点与x轴的两个交点构成的三角形是直角三角形,则这种抛物线就称为:“美丽抛物线”.如图,直线l:y=13x+b经过点M(0,14),一组抛物线的顶点B1(1,y1),B2(2,y2),B3(3,y3),…Bn(n,yn) (n为正整数),依次是直线l上的点,这组抛物线与x轴正半轴的交点依次是:A1(x1,0),A2(x2,0),A3(x3,0),…An+1(xn+1,0)(n为正整数).若x1=d(0<d<1),当d为( )时,这组抛物线中存在美丽抛物线.