表示班轮航线上各港口的平均装卸效率和组织管理水平，决定着航线上船舶的在港时间的班轮航

Bungee jumping is not a new activity. Men on Pentecost Island in the South Pacific have been doing land jumping for hundreds of years. The men tie long vines(藤) from plants around their ankles（踝关节）. They spend days building tall towers out of vines and logs(圆木). Then they jump off them.

According to their beliefs, the first land diver was a woman. She decided to run away from her rude husband. So she climbed up a tall tree and tied some vines around her feet. Her husband also climbed up the tree and tried to catch her, but the woman jumped and the man followed. The vines saved her life, but her husband died.

This ancient custom caught the interest of some students at Oxford University in England. In the late 1970s, they formed a group called the Dangerous Sports Club. They were some of the first people to test several of what are now called extreme sports. They are said to have invented modern bungee jumping.

In the spring of 1979, members of the group jumped off the Clifton Suspension Bridge in Bristol, England. They were attached to the bridge by a bungee cord, a long elastic rope that stretches. The group soon received even more attention when they organized a bungee jump off the Golden Gate Bridge in San Francisco, California.

A man named A. J. Hackett of New Zealand decided to make the sport into a business. He started developing bungee ropes and material with a friend. They held a major jump in 1987 off the famous Eiffel Tower in Paris, France. They later got permission to open the first bungee jumping operation on the Kawarau Bridge in Queenstown, New Zealand. Many people paid 75 dollars to jump off the bridge with a bungee cord attached to their ankles.

小题1:The second paragraph tries to tell us________________.

A．a story about a woman land diver

B．the beginning of modern bungee jumping

C．the beginning of land jumping on Pentecost Island

D．a story about a brave woman and her rude husband小题2:The underlined word them in the first paragraph refers to__________.

A．plants

B．tall towers

C．vines

D．logs小题3: The Dangerous Sports Club first caught people’s attention when they jumped off_________.

A．the Eiffel Tower

B．the Kawarau Bridge

C．the Golden Gate Bridge

D．the Clifton Suspension Bridge

请回答下列与哺乳动物精子和卵子发生有关的问题：

(1)精细胞经变形后，高尔基体发育形成精子的顶体，顶体内含有的____能协助精子穿过卵母细胞的放射冠和透明带。

(2)某动物排卵时，减数第一次分裂尚未完成，此时卵子处于______卵母细胞阶段，当该细胞发育至减数第二次分裂_________期时，才具备受精能力。若在卵黄膜和透明带之间看到两个极体，则表明____过程已完成。

(3)动物的早期胚胎移植到同种且____与供体相同的动物体内，使之继续发育为新个体的技术叫做胚胎移植。为了获得更多的早期胚胎，常用____激素对供体进行处理，其目的是获得更多的____，经人工授精后可得到早期胚胎。用某染料鉴定胚胎细胞是否为活细胞时，发现活胚胎细胞不能被染色，其原因是活细胞膜__________。

(4)若要通过胚胎移植获得遗传物质完全相同的两个新个体，可对发育到桑椹期或囊胚期阶段的早期胚胎进行_________处理，再植入到受体内。若要对早期胚胎进行长期保存，应将其置于_______条件下。

幼儿园班级管理的目的和意义有哪些？

在某些食品的包装袋内，有一个白色颗粒状的小纸袋，上面写着“干燥剂，主要成分为生石灰”．小丽发现纸袋内的白色颗粒粘在一起成为块状．于是她叫来了小露、小叶和她们一起来对白色物质进行了如下的探究．根据所学的知识，三位同学就该白色粉末作出了不同的猜想：

①小露的猜想是氢氧化钙，其理由是（用化学方程式表示）______；

②小叶的猜想是______，其理由是（用化学方程式表示）______； 

③小丽的猜想是______．于是她们设计了以下的实验：

（1）小露取少量的白色粉末溶于水，待澄清后，用滴管将液体滴到pH试纸上，发现其pH______，于是小露认为白色粉末就是氢氧化钙．

（2）小叶取少量白色粉末于试管中，滴加了稀盐酸，发现有大量的气泡产生．其反应的原理是（用化学方程式表示）______．于是小叶就认为自己的猜想是正确的．

（3）小丽认为小露和小叶的实验不足以证明白色粉末的成分．认为小露的结论不正确，理由是______；认为小叶的结论不正确，理由是______．在此基础上，小丽重新设计了实验：小丽取少量白色粉末溶于水中，待澄清后，滴加了无色酚酞试液，发现溶液变红，小丽将上层清夜倒掉后，向试管里的固体残渣中滴加了稀盐酸，产生了______．于是小丽就证明了自己的猜想．

读下图，从城区环保角度考虑，四个工厂布局比较合理的是

A．砖瓦厂

B．有色金属冶炼厂

C．造纸厂

D．电镀厂