不被固定相吸附或溶解的气体,从进样开始到柱后出现浓度最大值所需要的时间是()。A、固

题型:单项选择题

问题:

不被固定相吸附或溶解的气体,从进样开始到柱后出现浓度最大值所需要的时间是()。

A、固定时间

B、死时间

C、保留时间

D、相对保留时间

考点:食品检验工考试食品检验工考试题库
题型:单项选择题

While the presence of rats in homes may cause anxiety and annoyance, they rarely result in driving out the residents. But that is exactly what happened to the inhabitants of the 10­square­mile Hawadax Island off the coast of Alaska, almost 230 years ago. Now thanks to a five­year effort by scientists, the terribly silent “Rat Island” as it had been called for many years has been returned to its rightful owners ——birds!

Hawadax Island is part of a chain of volcanic islands in the Bering Sea called the Aleutian Islands. The rats that arrived there in 1780, when a Japanese ship carrying them broke down nearby, completely destroyed the native population because the environment of the island was not built to defend its animals from these predators. There isn't any tree on the Island, which meant that the birds were accustomed to building their nests low in the ground, giving the rodents(啮齿动物) easy access to both eggs and baby chicks. As years passed, the birds that had called the island home for thousands of years became endangered and eventually, disappeared completely.

In 2007, the U.S. FWS (Fish and Wildlife Service) started a serious plan to rid the island of the rats and try bringing back the beautiful birds that had once called it home. Given that there were an estimated 10,000 rodents inhabiting “Rat Island” and the fact that they re­produce rapidly, it was not an easy task. But by 2009, the Island was officially declared rat free!

Then slowly but surely, the birds began to return. Unfortunately, some of the pioneers were unintentionally killed from the leavings of the raticide, a poison that had been used to wipe out the rodents. But now it seems things are becoming more stable and the Island is starting to increasingly look like its former self. Before the transformation, “Hawadax”, also known as “Rat Island”, was a silent and ghostly place with bird bones, snail remains and rocks covered in rat feces(粪便).

Today, birds' singing and flying in and out is a common sight. Tufted puffins and song sparrows, which had long disappeared, are gradually making their way back. Scientists have also been observing an increase in ground nesting and shorebirds. Though the Island is still not back to its full glory, the signs are encouraging and things can only get better, as time passes.

小题1:The underlined word “that”in Para.1 probably refers to ________.

A.the presence of rats

B.birds' being driven out

C.birds' returning to the island

D.residents' worrying about rats小题2:Birds on Hawadax Island became an easy target because ________.

A.this island was treeless

B.they nested randomly

C.they reproduced too rapidly

D.their chicks were extremely weak小题3:From the passage, we can know the plan of US FWS ______.

A.has helped the island fully recovered

B.cost little but benefited greatly

C.involved poisoning the rats on a large scale

D.accomplished its goal after exactly 24 months小题4:Which would be the best title for the passage?

A.FWS Help Get Rare Birds Back to Alaska Island

B.Japanese Changed a Bird Paradise into Rat Island

C.FWS Plan to Drive Rats Out Of Rat Island

D.Alaska's Rat Island Returns to a Bird Paradise

题型:单项选择题

在考生文件夹下的“samp1.mdb”数据库文件中已经建立了表对象“tStud”。请按以下操作要求,完成表的编辑修改。

将“编号”字段改名为“学号”,并设置为主键。

题型:单项选择题

金融市场利率的决定因素包括()

A.纯利率

B.通货膨胀补偿率

C.流动性风险报酬率

D.期限风险报酬率

E.违约风险报酬率

题型:单项选择题

对发生过收、发的商品即时核对该批商品余额是否与帐、卡相符的盘点方法是()。

A.动态盘点

B.循环盘点

C.全面盘点

D.重点盘点

题型:单项选择题

情商和智商的区别有()。

A.智商和情商反映着两种性质不同的心理品质

B.智商和情商的形成基础有所不同

C.智商和情商的作用不同

D.都是人的重要的心理品质,都是事业成功的重要基础

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