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问题 单项选择题

火灾探测器的导线用铜导线时，其截面应不小于（）。

A．0.75mm2

B．1.0mm2

C．1.5mm2

D．2.5mm2

答案

参考答案：A

解析：

探测器的导线用铜芯线，截面不小于0.75mm2，用多股或单股都可以。

单项选择题

诊断HPV最可靠的方法是（）

A.以上都不是

B.原位杂交

C.DNA印迹

D.PCR

E.核酸分析
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单项选择题

Every object tells a story. Even the most ordinary objects can present to us powerful images. Sometimes it is the ordinary nature of these objects that actually makes them so extraordinary. Such is the case with an old leather shoe in a museum in Alaska. At first glance it does not look like much. It is a woman’s shoe of a style popular in the 1890s. But what is unique about this shoe is where it was found. It was discovered on the Checkout Pass, the famous trail used by the people seeking gold in Alaska. Who it belonged to or why it was left there is not known. Was it perhaps dropped by accident as the woman climbed up the 1500 stairs carved outface Or did she throw away goods that she didn’t need in order to travel lighter
Over 100000 people with "gold fever" made this trip hoping to become millionaires. Few of them understood that on their way they would have to cross a harsh wildness. Unprepared for such a dangerous journey, many died of starvation and exposure to the cold weather.
The Canadian government finally started requiring the gold seekers to bring one ton of supplies with them. This was thought to be enough for a person to survive for one year. They would carry their supplies in backpacks each weighing up to fifty pounds; it usually took at least 40 trips to get everything to the top and over the pass. Whoever dropped the shoe must have been a brave and determined woman. Perhaps she was successful and made it to Alaska. Perhaps she had to turn back in defeat. No one will ever know for sure, but what we do know is that she took part in one of the greatest adventures in the 19th century.

According to this passage, many people who went to Alaska ______.

A. eventually became millionaires
B. brought with them many shoes
C. had conflicts with the Eskimos
D. were not properly equipped
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