Facebook currently holds more than 45 billion photos in its user database, a number that is growing daily.

Despite overwhelming scientific evidence that tobacco causes more than 400 000 deaths each year, our nations children continue to have easy access to cigarettes and spit tobacco. There are no significant restrictions on tobacco marketing that target teenagers, no national anti-smoking programs under way, and none on the drawing board. Despite all the research on the dangers of secondhand smoke, there are no nationwide protections against it. To top it all off, the United States has among the weakest package warnings and the lowest tobacco product prices in the industrialized nations of the world. Yet, we now have the opportunity to finally address the biggest and most preventable health problem facing this nation. After a long and thorough analysis, President Clinton has come forward with a statement of principles and direction for a national tobacco control plan that represents a major step.

A new survey by Harvard University finds more than two-thirds of young Americansdisapprove of President Trump’s use of Twitter The implication is that Millennials prefer newsfrom the White House to be filtered through other source， Not a president’s social mediaplatform.

Most Americans rely on social media to check daily headlines Yet as distrust has risentoward all media， people may be starting to beef up their media literacy skills Such a trend isbadly needed.During the 2016 presidential campaign， nearly a quarter of web content sharedby Twitter users in the politically critical state of Michigan was fake news， according to theUniversity of Oxford And a survey conducted for BuzzFeed News found 44 percent of Facebookusers rarely or never trust news from the media giant.

Young people who are digital natives are indeed becoming more skillful at separating factfrom fiction in cyberspace.A Knight Foundation focus-group survey of young people betweenages 14and24 found they use “distributed trust” to verify stories They cross-check sourcesand prefer news from different perspectives—especially those that are open about any bias “Many young people assume a great deal of personal responsibility for educating themselvesand actively seeking out opposing viewpoints，” the survey concluded.

Such active research can have another effect A 2014 survey conducted in Australia，Britain， and the United States by the University of Wisconsin-Madison found that young people’ s reliance on social media led to greater political engagement.

Social media allows users to experience news events more intimately and immediately whilealso permitting them to re-share news as a projection of their values and interests.This forcesusers to be more conscious of their role in passing along information A survey by Barnaresearch group found the top reason given by Americans for the fake news phenomenon is“reader error，” more so than made-up stories or factual mistakes in reporting About a thirdsay the problem of fake news lies in “misinterpretation or exaggeration of actual news” viasocial media In other words， the choice to share news on social media may be the heart of theissue “This indicates there is a real personal responsibility in counteracting this problem，” saysRoxanne Stone， editor in chief at Barna Group.

So when young people are critical of an over-tweeting president， they reveal a mentaldiscipline in thinking skills – and in their choices on when to share on social media.

According to the Paragraphs 1 and 2， many young Americans cast doubts on_________.

A.the justification of the news-filtering practice

B.people’s preference for social media platforms

C.the administrations ability to handle information

D.social media was a reliable source of news

The phrase “beer up”（Line 2， Para 2） is closest in meaning toA.sharpen

B.define

C.boast

D.share

Which of the following would be the best title for the text？A.A Rise in Critical Skills for Sharing News Online

B.A Counteraction Against the Over-tweeting Trend

C.The Accumulation of Mutual Trust on Social Media

D.The Platforms for Projection of Personal Interests

The Barna survey found that a main cause for the fake news problem isA.readers outdated values

B.journalists’ biased reporting

C.readers’ misinterpretation

D.journalists’ made-up stories

According to the knight foundation survey， young peopleA.tend to voice their opinions in cyberspace

B.verify news by referring to diverse resources

C.have s strong sense of responsibility

D.like to exchange views on “distributed trust”

请帮忙给出每个问题的正确答案和分析，谢谢！

UsersinyourproductiondatabasecomplainthattheyaregettingthefollowingerrormessagewhiletryingtoinsertrowsintotheORDERStable：ERRORatline1：ORA-01654：unabletoextendindexUSERS.ORDERS_INDby8intablespaceINDEXES.Whileinvestigating，youfindthattheINDEXEStablespacehasrunoutofspaceandthereisnomorefreespaceonthediskwherethedatafilesareavailable.Whichtwoactionscouldyouperformtoovercomethiserrorwithoutaffectingthequeriesthatarecurrentlybeingexecuted？（）

A.Dropandre-createtheinbox.

B.CoalescetheORDERS_INDindex.

C.CoalescetheINDEXEStablespace.

D.Dropandre-createtheORDERStable.

E.Rebuildtheindexonlineandmoveittoanothertablespace.

UsersinyourproductiondatabasecomplainthattheyaregettingthefollowingerrormessagewhiletryingtoinsertrowsintotheORDERStable：ERRORatline1：ORA01654：unabletoextendindexUSERS.ORDERS_INDby8intablespaceINDEXESWhileinvestigating，youfindthattheINDEXEStablespacehasrunoutofspaceandthereisnomorefreespaceonthediskwherethedatafilesareavailable.Whichtwoactionscouldyouperformtoovercomethiserrorwithoutaffectingthequeriesthatarecurrentlybeingexecuted？（）

A.dropandrecreatetheindex

B.coalescetheORDERS_INDindex

C.coalescetheINDEXEStablespace

D.dropandrecreatetheORDERStable

E.rebuildtheindexonlineandmoveittoanothertablespace

听力原文： Let me remind you that ours is not the only planet with a moon. In fact, lots of the other planets in the solar system have one, and some have more than one. Take Mars, for example. The large red planet actually has two, Phobos and Deimos. Now, Phobos is the focus for this lecture. Well, to begin with, it is much closer to Mars than our moon is to us. In fact, of all the moons in the solar system, its the closest to its planet. And it moves rather quickly as it completes its small orbit. When we talk about planets and moons there is something called the synchronous orbit radius, which is the size and speed of the orbit a moon needs in order to spin around its planet at the same speed as the planet spins around itself. Think of it this way, when a moon reaches synchronous orbit radius, you can stand on the planets surface and the moon will always stay in the same place in the sky. If a moon is below this orbit, like Phobos is, then it actually rises and sets more than once a day. OK, so we know that Phobos is close to Mars and therefore seems to move quickly across its sky. I guess the next question that needs to be answered is related to what the moon is made of? Well, were not really sure, but we have some good guesses. First, most of the material is likely similar to what you would find in a C-type asteroid, which is nothing more than different types of carbon. So, its like ninety percent carbon. Covering the moon is a one-meter-deep layer of something called regolith. Now, the fact is that its just a fancy scientific word for a loose layer of material covering rock. A lot of time regolith is just dust or sand, but if it has a lot of organic material in it, we call it soil, just like you would use in a garden. Phobos is made up of a dust covering and rock underneath, but it is not dense enough to be solid rock to its core. So, its also likely that the center is made up of ice. In fact, the Russians managed to send a probe to Phobos and observed off gassing, which means that they could detect gases being released from the moon. Unfortunately, the probe stopped working before they could identify the gases, but scientists generally believe that it was water vapor. If you look at these characteristics all together, you can start to see a good argument for the idea that Phobos is just an asteroid that got caught in Martian gravity. I forgot to mention this, but now would be a good time. Phobos is not really that big. Its only 27 km by 21.6 km by 18.8 km. That makes it smaller than Marss other moon, in fact, smaller than most moons we know of. I wanted to include that because it supports the argument that its just an asteroid pretending to be a moon. Its not really big enough to be anything else. We know where it is and what it might be made of. Now lets look to the future. Phobos loses about 1.8 meters of its distance from Mars every one hundred years. Eventually, its going to hit the planet, right? Well, thats not the case. The moon will fall apart before it gets to the surface. Actually, in about fifty million years, the moon is going to dip down below something called the Roche limit. When that happens, the gravity that holds the moon together will be overcome by the tidal gravity of the planet. The moon will basically fall apart and the smaller pieces will become a planetary ring. Think about the planet Saturn and the rings it has around it. Mars will have the same thing, made up of little bits of Phobos. So, its like ninety percent carbon. Covering the moon is a one-meter-deep layer of something called regolith. Now, the fact is that its just a fancy scientific word for a loose layer of material covering rock. A lot of time regolith is just dust or sand, but if it has a lot of organic material in it, we call it soil, just like you would use in a garden. Why does the professor say this: Now, the fact is that its just a fancy scientific word for a loose layer of material covering rock.

What is the topic of the lecture?

A．Distant asteroids.

B．Earth"s moon.

C．Mars"s moon.

D．Lunar orbits.