1.单选题- (共19题)
| A．延长射线AB到点C，使BC=2AB |
| B．点P在线段AB上，点Q在直线AB的反向延长线上 |
| C．将射线OA绕点O旋转180°，终边OB与始边OA的夹角为一个平角 |
| D．已知线段a，b满足2a＞b＞0，在同一直线上作线段AB=2a，BC=b，那么线段AC=2a-b |
| A．甲同学 | B．乙同学 | C．丙同学 | D．丁同学 |
| A．三角形的一个内角为60°，一条边长为3cm |
| B．三角形的两个内角为30°和70° |
| C．三角形的两条边长分别为3cm和5cm |
| D．三角形的三条边长分别为4cm、5cm和8cm |
| A．过直线外的一点画已知直线的平行线 |
| B．过直线上的一点画已知直线的垂线 |
| C．过∠AOB内的一点画∠AOB的平分线 |
| D．过直线外一点画此直线的两条斜线，一条垂线 |
| A．过点P作线段AB的中垂线 |
| B．在线段AB的延长线上取一点C，使AB=BC |
| C．过直线a，直线b外一点P作直线MN使MN∥a∥b |
| D．过点P作直线AB的垂线 |
| A．过点P作线段AB的中垂线 |
| B．在线段AB的延长线上取一点C，使AB=AC |
| C．过点P作线段AB的垂线 |
| D．过直线a，b外一点P作直线MN，使MN∥a∥b |
2.选择题- (共16题)
Google, one of the world's outstanding tech companies, was attacked. It wasn't its search engine that was attacked or its advertising platform or even its social network, Google+. Instead, it was a building.
Two web security experts hacked (侵入) into its Wharf 7 office in Sydney, Australia, through Google's building management system (BMS). One of them, Billy Rios, says, “My colleague and I have a lot of experience in web security, but it is not something that people couldn't learn. Once you understand how the system works, it is very simple.”
They found the system on Shodan, a search engine that lists devices connected to the Internet, and then ran it through their own software to identify who owned the building. In the case of the Google hacking, the researchers had no immoral purpose and just informed Google about what they found.
According to Mr. Rios, Who runs security company Whitescope, there are 50,000 buildings currently connected to the Internet, including research institutes, churches and hospitals, and 2,000 of those are online with no password protection. Martyn Thomas, a professor of IT at Gresham College in the UK, says, “It is beyond doubt that attempts to attack building management systems arc happening all the time.”
Making a building smart generally means connecting the systems that control heating, Hating and security to the Internet and the wider corporate network. There was a strong reason for doing this, said Andrew Kelly, principal security consultant at defence company Qinetiq.
“Energy savings are the biggest factor in connecting building management systems to the corporate network,” he says. “It gives those who run the building better control and offers between 20% to 50% in energy savings,” he adds.
But it also makes them less secure. And if any of these feels like a Hollywood film, think again.
Google, one of the world's outstanding tech companies, was attacked. It wasn't its search engine that was attacked or its advertising platform or even its social network, Google+. Instead, it was a building.
Two web security experts hacked (侵入) into its Wharf 7 office in Sydney, Australia, through Google's building management system (BMS). One of them, Billy Rios, says, “My colleague and I have a lot of experience in web security, but it is not something that people couldn't learn. Once you understand how the system works, it is very simple.”
They found the system on Shodan, a search engine that lists devices connected to the Internet, and then ran it through their own software to identify who owned the building. In the case of the Google hacking, the researchers had no immoral purpose and just informed Google about what they found.
According to Mr. Rios, Who runs security company Whitescope, there are 50,000 buildings currently connected to the Internet, including research institutes, churches and hospitals, and 2,000 of those are online with no password protection. Martyn Thomas, a professor of IT at Gresham College in the UK, says, “It is beyond doubt that attempts to attack building management systems arc happening all the time.”
Making a building smart generally means connecting the systems that control heating, Hating and security to the Internet and the wider corporate network. There was a strong reason for doing this, said Andrew Kelly, principal security consultant at defence company Qinetiq.
“Energy savings are the biggest factor in connecting building management systems to the corporate network,” he says. “It gives those who run the building better control and offers between 20% to 50% in energy savings,” he adds.
But it also makes them less secure. And if any of these feels like a Hollywood film, think again.
移植总数n | 400 | 1500 | 3500 | 7000 | 9000 | 14000 |
成活数m | 325 | 1336 | 3203 | 6335 | 8073 | 12628 |
成活的频率（精确到0.01） | 0.813 | 0.891 | 0.915 | 0.905 | 0.897 | 0.902 |
由此估计这种幼树在此条件下移植成活的概率约是{#blank#}1{#/blank#}（精确到0.1）
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【1】题量占比
单选题:(19道)
选择题:(16道)
-
【2】：难度分析
1星难题：0
2星难题：0
3星难题：0
4星难题：0
5星难题：0
6星难题：0
7星难题：0
8星难题：1
9星难题：18