胶质通常褐色至暗褐色的粘稠而流动性很差的液体。

根据短文意思，在41～50各题的空格里填入一个恰当的词语，使句子通顷、完整。

     Long, long ago, people didn't have telephones 1_____ other modern ways to send messages to others,

but they still could send messages 2_____ many different ways. A man put his ear to the ground. 3_____

he heard the sound of the horses, he quickly ran to tell his people. He was a runner. That was one way

to send messages.

     People 4_____ sent messages by smoke. One man made a cloud of smoke. In the next place people

saw the smoke and went on doing that, too. The message thus went from one place 5_____ another by

smoke.

     Much later, some soldiers kept many pigeons (鸽子). These pigeons always flew back. When a soldier

was sent far 6_____ from his place, he might carry 7_____ pigeon with him. He could write a message

8_____ put it on the bird's leg. 9_____ would fly back with the soldier's message.

     These are some ways to send messages. 10_____ you think of some faster ways?

将一些苹果储藏在密闭容器中，较长时间后会闻到酒香。若细胞呼吸的底物都是葡萄糖，当通入不同浓度的氧气时，其O₂的消耗量和CO₂的产生量如表所示，则下列叙述错误的是

A．氧浓度为a时，苹果的细胞呼吸只在细胞质基质中进行

B．氧浓度为c时，苹果产生C₂H₅OH的量为0.6mol/min

C．氧浓度为d时，消耗的葡萄糖中有1/4用于酒精发酵

D．氧浓度为b时，较适宜于苹果的储藏

罗马法是罗马统治的有力支柱。在罗马共和国时期，罗马法主要用来调整

A．罗马公民之间的关系

B．罗马公民与非公民之间的关系

C．商品生产者之间的关系

D．奴隶主与奴隶之间的关系

2011年3月30日，南京市举办“追忆历史名人，弘扬科学创新精神”的活动，纪念祖冲之等科学家，通过此次活动市民了解到祖冲之作出的杰出贡献。你知道祖冲之的“杰出贡献”中，最突出的是哪一领域吗（）

A.数学

B.天文学

C.医学

D.地理学