For (1) service, we need a virtual-circuit subnet. Let us see how that works. The idea behind virtual circuits is to avoid having to choose a new (2) for every packet sent. Instead,when a connection is established, a route from the(3) machine to the dest

共用题干
One Good Reason to Let Smallpox Live
It's now a fair bet that we will never see the total extinction of the smallpox virus. The idea was to cap the glorious achievement of 1980,when smallpox was eradicated in the wild,by destroying the killer vims in the last two labs that are supposed to have it one in the US and one in Russia. if smallpox had truly gone from the planet,what point was there in keeping these reserves?
_______(51)reality,of course,it was naive to _______(52)that everyone would let ________(53)of such a potent potential weapon. Undoubtedly several nations still have _______(54)vials._______(55)the last“official”stocks of live virus bred mistrust of the Us and Russia,_______ (56)no obvious gain.
Now American researchers have________(57)an animal model of the human disease,opening the________(58)for tests on new treatments and vaccines.So once again there's a good reason to_______(59)the virusjust in_______(60)the disease puts in a reappearance.
How do we_______(61)with the mistrust of the US and Russia?_______(62).Keep the virus________(63)international auspices in a well-guarded UN laboratory that's open to all countries. The US will object,of course,just at it rejects a multilateral approach to just about everything. But it doesn't_______(64)the idea is wrong. If the virus_______(65)useful, then let's make it the servant of all humanity—not just a part of it.

61._________
A:. handle
B: tackle
C: deal
D: treat

We experience a burst of pleasure when we share our thoughts,and this drives us to communlcate.It is a useful feature of our brain,because it ensures that knowledge,experience and ideas do not get buried with the person who first had them,and that as a society we benefit from the products of many minds.Of course,in order for that to happen,merely sharing is not enough.We need to cause a reaction.Each time we share our opinions and knowledge,it is with the intention of having an impact on others.Here's the problem,though:we approach this task from inside our own heads.When attempting to create impact,we reflect on what is persuasive to us,our state of mind.our desires and our goals.But if we want to affect the behaviours and beliefs of the person in front of us,we need to understand what goes on inside their head.

In our comparison-soaked culture, it′s hard to avoid slipping into "Why can′t I" mode. When one of my colleagues (51)__________I think is not better than me published a new book, I couldn′t help (52) __________ (complain) how (53) __________ (achieve) it seemed to me and what bad luck I had. Negative feelings like this made life dark for us. How to get rid of the harmful effects of comparison needs exploring. Here′ s what I learned:
Don′ t compare your insides to someone else′ s outsides.
The first time I heard this excellent advice, I (54)__________(suffer) from terrible envy. My professor′s warning shocked me that "You have no idea what it (55) __________ (take) for them to get there". Don′t just owe it to pure luck. Instead, you should fad out what′s really going on behind the scenes.
She was absolutely right, yet it′s much (56) __________ (easy) to envy what they′ve got than it is to ask the serious question: What are they modeling for me? What have they done to get (57) __________ they are today? When we reflect (58)__________ these questions, we shift immediately out of comparison mode and turn inwards.
Transform comparison into celebration.
Admiration and envy are responses pointing us toward what we value most. And once we become aware of what we value, we are much better positioned (59)__________ (create) a richly satisfying life. If you notice yourself admiring people who take creative risks, bring your full attention to the part of you that wants to be braver.
Use the success of others as a mirror.
Next time you catch yourself admiring or envying someone′s success, take a moment to consider: What qualities in them inspire me? Where do I presently display these qualities? Remember the light we see in (60) __________ can help us see our own.
第（53）题答案

It's almost impossible to go through life without experiencing some kind of failure.People who do so probably live so cautiously that they go nowhere.Put simply,they’re not real living at all.But,the wonderful thing about failure is that it's entirely up to us to decide how to look at it.We can choose to see failure as"the end of the world,"or as proof of just how inadequate we are.Or,we can look at failure as the incredible learning experience that it often is.Every time we fail at something,we can choose to look for the lesson we're meant to learn.These lessons are very important;they're how we grow,and how we keep from making that same mistake again.Failures stop us only if we let them.Failure can also teach us things about ourselves that we would never have learned otherwise.For instance,failure can help you discover how strong a person you are.Failing at something can help you discover your truest friends,or help you find unexpected motivation to succeed.