Is a whale a mammal or a fish?What is the meanin

How was the gap between a walking mammal and a swimming whale bridged?请问bridged什么意思?
How was the gap between a walking mammal and a swimming whale bridged?Missing until recently were fossils clearly intermediate,or transitional,between land mammals and cetaceans.请问bridged什么意思,为什么放句末,后面一句结构不明白,用软件翻译给我的别填,用网上已有的回答敷衍的也别填,浪费你我的时间,

As is known to all,the whale is not fish but a mammal.
这句话中为什么fish前面不加a而mammal前面要加a呢?

英语语法问题
The whale is the world`s largest mammal.请问这里的world`s 能够把s去掉,写出world的啊

Generally,the thicker a mammal's skin is,the less hair____
A.that has it B.that it has C.has it D.it has
考察的是那部分知识啊?

英语翻译
Ecologists,thought,cannot observe these energetic mammals scurrying upand down oak trees and eating and burying acorns without wondering about theircomplex relationship with trees.
为什么 thought 放在后面,

The first mammal (clone) from an adult cell was Dolly the sheep.

SAT的几道语法题
1.The reason the mammal is the dominant life form in such a wide range of habitats is its ability to maintain a steady internal body temperature in practically any environment.
practically any错了，为什么？
2.Elizabeth Ellet is best known for her historical accounts that focus on ordinary lives,especially that of women,rather than on larger political and socioeconomic events.
that of 错了。我觉得 rather than错了啊，是不是应该改成 rather than that啊。
3.Despite its dry climate,the ancient city of Petra had about 30000 resident; this astonishing dense population was made possible only by a cleverly designed water supply system.
astonishing为神马不对？

the white-flag dolphin,a rare chinese mammal depends on the yangtze river fo
为什么选 a rare ,the yangtze

memo和mammal发音有什么不同,能否用中文同音字说明一下?
memo和mammal发音有什么不同,能否用中文同音字说明一下每个音节的不同地方

.The reason the mammal is the dominant life form in A（such a wide range of habitats ）is its ability to maintain a steady internal body temperature in B（practically any ）environment.
为什么A中是a 后面不是habitat吗 然后B为什么是对的

英语翻译
Compare the dessert-dwelling mammal you researched and a human in terms of the:
a) ways in which they obtain water
b) amount of water required to survive
c) amount of water lost by evaporation
d) relative concentration of urine produced
e) amount and/or frequency of urination

动物的分类（要英语的）
比如说:哺乳类(mammal)的动物，鸟类(bird)的动物，爬行类(reptil)的动物，鱼类(fish)的动物，等等。

来做几道英语选择题．说明理由
1.but man and some monkeys are the only mammals ( )can see color
A.which B.who C.when D.that
2.like ( ) animals ,dogs seebest when things move
A.for B.with C.as D.to
3.the animals they hunt seem to know( ) .
A.them B.these C.this D.so
4.a young bird can see a house ( )the sky
A./ B.from C.on D.at
5.the bird can ( ) something they think safe
A.land B.land on C.land for D.be landed
一定要说明理由