小明是这样完成“作∠MON的平分线”这项作业的：

“如图，①以O为圆心，任意长为半径画弧，分别交OM、ON于点A、B；②分别作线段OA、OB的垂直平分线l₁、l₂（垂足分别记为C、D），记l₁与l₂的交点为P；③作射线OP，则射线OP为∠MON的平分线”．

你认为小明的作法正确吗？如果正确，请你给出证明，如果不正确，请指出错在哪里．

狮子   猩猩   羚羊   海龟   白鹤   鸽子   蚯蚓   螃蟹   蝴蝶   蚕

天上飞的：____

地上跑的：____

水里游的：____

没有腿的：____

用方框中所给单词的适当形式填空，使短文通顺、正确、连贯（每个单词限用一次）

To: Christin foo@hotmail.com

Date: 23^rd March
Subject: The Riding for the Disabled Association
Hi Christine,
Sorry I haven't emailed lately —I've been very busy since becoming a volunteer for the Riding for the Disabled Association.
Every Saturday, I help to get the horses ____  for the disabled(残疾) riders. Many more disabled people want to ride ____ than you'd imagine. It's a disadvantage that I don't know how to ride —I'd love to got on long rides with the riders— but I'll learn soon ____ . Right now, I'm just happy to be able to lead the horses around for the disabled riders.
    I'm____  helping to organize a sale, which will be ____  next month. It's a lot more work than helping the disabled. I need to collect second-hand things to sell at the sale. There are ____  things available(获得的) than I thought, but I'm sure we'll have enough____  next month.
     I hope the sale raises more money than last month's walk. It was rainy, so too few people took part in the event. Last week, we held an auction(拍卖). The auction took much less ____ to organize than the walk. ____ , for some reason, people offered too little money for the things, so we didn't raise enough money.
     I'm ____ you some pictures in the letter, as well as a speech I gave last week.

已知函数$f\left(x\right)=a{x}^3+b{x}^2+cx+d$在O，A点处取到极值，其中O是坐标原点，A在曲线$y=x^2\sin x+x\cos x,x\in \frac{\mathrm{\pi }}{3},\frac{2\mathrm{\pi }}{3}$上，则曲线$y=f\left(x\right)$的切线的斜率的最大值是（  ）