口径（）mm以及更大的混凝土管通常都加钢筋 A.300 B.500 C.800 D.

闸门的支撑滑块还是滚轮，检查方法就是进行（）。

A、闸门启闭试验

B、抗压检测

C、强度试验

D、摩阻试验

在桥梁荷载试验中，一般静载试验效率选在（）范围之内。

用重为15N的桶从井中提水，在桶未露出水面时，提起这桶水所用的力是（　　）

A．等于15N

B．大于15N

C．小于15N

D．无法确定

Global Positioning Systems are now a part of everyday driving in many countries. These satellite-based systems provide turn-by-turn directions to help people get to where they want to go. But, they can also cause a lot of problems, send you to the wrong place or leave you completely lost. Many times, the driver is to blame. Sometimes a GPS error is responsible. Most often, says Barry Brown, it is a combination of the two.

We spoke to Mr. Brown by Skype. He told us about an incident involving a friend who had flown to an airport in the eastern United States. There he borrowed a GPS-equipped car to use during his stay. Barry Brown: “And they just plugged in an address and then set off to their destination. And, then it wasn’t until they were driving for thirty minutes that they realized they actually put in a destination back on the West Coast where they lived. They actually put their home address in. So again, the GPS is kind of 'garbage in garbage out'.”

Mister Brown says this is a common human error. But, he says, what makes the problem worse has to do with some of the shortcomings, or failures, of GPS equipment. Barry Brown: “One problem with a lot of the GPS units is they have a very small screen and they just tell you the next turn. Because they just give you the next turn, sometimes that means that it is not really giving you the overview that you would need to know that it’s going to the wrong place.”

Barry Brown formerly served as a professor with the University of California, San Diego. While there, he worked on a project with Eric Laurier from the University of Edinburgh. The two men studied the effects of GPS devices on driving by placing cameras in people’s cars. They wrote a paper based on their research. It is called “The Normal, Natural Troubles of Driving with GPS.” It lists several areas where GPS systems can cause confusion for drivers. These include maps that are outdated, incorrect or difficult to understand. They also include timing issues related to when GPS commands are given.

Barry Brown says to make GPS systems better we need a better understanding of how drivers, passengers and GPS systems work together.

小题1:In Paragraph 2, Mr. Brown mentioned his friend in the conversation to _____________.

A．build up his own reputation

B．laugh at his stupid friend

C．prove the GPS system is only garbage

D．describe an example of human error小题2:With which of the following statement would Barry Brown most likely agree?

A．GPS units are to blame for the most GPS service failures.

B．We should introduce higher standard for the driving license.

C．Cameras are urgently needed to help improve GPS systems.

D．Drivers, GPS systems and passengers should unite to improve GPS systems.小题3:What is Mr. Brown’s attitude towards GPS?

A．Unconcerned

B．Prejudiced

C．Objective

D．Critical小题4:What would be the best title for the text?

A．driving with GPS can be difficult

B．driving confusions can be caused by small screen

C．driving without GPS should be much more convenient

D．GPS equipment in driving: to be deserted or improved?

柴油机在船舶上除用作推进发动机一主机之外，还广泛地用作发电机原动机，动力型救生艇发动机，应急消防泵原动机等。