单选题In paragraphs 4 and 5 the author discusses that______.A mastering Russian is the key to success in the Soviet Union.B citizens of China should focus on the acquisition of Mandarin.C English reaches its present global status as a world language.D langua

资料：Economic performance is improving in most of the world's leading economies but is still short of a self-sustaining upswing, the Organization for Economic Cooperation and Development said on Wednesday.
In an update to its economic forecasts, the Paris-based international organisation representing advanced economies said that more private sector investment was needed for the expansion to endure, for wages to rise sustainability and for inequalities to be tackled.
Although all leading economies are now recording positive growth, Catherine Mann, the OECD's chief economist, urged governments to “curb your enthusiasm [ because] strong and sustained medium-term global growth is not yet secured”.
The OECD's economic outlook shows upgrades to the 2017 growth forecasts in China, Russia and Europe excluding the UK with the world outlook also appearing stronger in 2018.
World growth should rise from a low of 3.1 per cent in 2016, to 3.5 per cent this year and 3.7 per cent in 2018, the OECD forecast, with the US, the Eurozone, Brazil and Russia contributing most to the improved global outlook.
China's predicted growth rate of 6.8 per cent in 2017 and 6.6 per cent in 2018 has been revised higher by 0.2 percentage points in both years and although India's growth rate has been revised down, reflecting adjustment to its new goods and services tax, it is likely to remain the fastest growing large economy in the world.
Only the UK, which remains embroiled in Brexit negotiations, has a deteriorating outlook. Responding to the OECD's forecast that the British economy will be the slowest growing in the Group of Seven in 2018 having been near the top of the league table in 2016, the British Treasury said it was not complacent.

What is the best title for the passage？

A.The prosperity of the leading economies
B.The engine of the world economy
C.China，the trail blazer of the world economy
D.Global economy improving but lacks self-sustaining upswing

In Paragraph 5, the author discusses that （　　）.

A.if labor costs continue to grow, it would ripple through the economy
B.average wages grow 19 percent from 2005 to 2010
C.foreign enterprises should switch their manufacturing to cheaper sources
D.the wage rises over the past 2 decades could be offset by rising production

One of the main reasons for getting students to listen to spoken English is to let them hear varieties and ___________, rather than just the voice of their teacher with its own idiosyncrasies. In today′s world, they need to be exposed not only to one variety of English, but also to varieties such as American English, Australian English, Indian English and so on.

A.languages
B.mother tongues
C.accents
D.natives

Text 4 To combat the trap of putting a premium on being busy,Cal Newport,author of Deep work:Rules for Focused Success in a Distracted World,recommends building a habit of“deep work”—the ability to focus without distraction.There are a number of approaches to mastering the art of deep work—be it lengthy retreats dedicated to a specific task;developing a daily ritual;or taking a“journalistic”approach to seizing moments of deep work when you can throughout the day.Whichever approach,the key is to determine your length of focus time and stick to it.Newport also recommends“deep scheduling”to combat constant interruptions and get more done in less time.“At any given point,I should have deep work scheduled for roughly the next month.Once on the calendar I protect this time like I would a doctor’s appointment or important meeting”,he writes.Another approach to getting more done in less time is to rethink how you prioritize your day—in particular how we craft our to-do lists.Tim Harford,author of Messy:The Power of Disorder to Transform Our Lives,points to a study in the early 1980s that divided undergraduates into two groups:some were advised to set out monthly goals and study activities;others were told to plan activities and goals in much more detail,day by day.While the researchers assumed that the well-structured daily plans would be most effective when it came to the execution of tasks,they were wrong:the detailed daily plans demotivated students.Harford argues that inevitable distractions often render the daily to-do list ineffective,while leaving room for improvisation in such a list can reap the best results.In order to make the most of our focus and energy.we also need to embrace downtime,or as Newport suggests,“be lazy.”“Idleness is not just a vacation,an indulgence or a vice;it is as indispensable to be brain as Vitamin D is to the body...[idleness]is,paradoxically,necessary to getting any work done,”he argues.Srini Pillay,an assistant professor of psychiatry at Harvard Medical School,believes this counter-intuitive link between downtime and productivity may be due to the way our brains operate When our brains switch between being focused and unfocused on a task,they tend to be more efficient.“What people don’t realise is that in order to complete these tasks they need to use both the focus and unfocus circuits in their brain”.says Pillay.
The key to mastering the art of deep work is to________.

A.keep to your focus time
B.list your immediate tasks
C.make specific daily plans
D.seize every minute to work

It is widely accepted that English is the global language of modern times.
About three decades ago,French was recognized as the language of diplomacy（外交）,and German was considered the language of science and technology.English now dominates（主导）not only as the language of science but also diplomacy,computing,and tourism.Today,in terms of native speakers,Mandarin Chinese is the world′s
largest language.
Yet there are people who believe that China will become the most powerful country in the world.Some have?even fixed the date as early as the year 2020.At present,while English is more widely spoken than any other?language,there are more people who speak Chinese than English due to the large population in China alone.If China?does become a world power,there is no doubt that this language will spread worldwide.
As the controversy over which language will become dominant in the world continues,there are many who feel?that the dominance of English is unique and irreversible（不可逆的）.However,a separate study from David Graddol′s suggests that English′s dominance in the scientific area will continue.There is also an argument that the?English language would be changed greatly by 2020 for various reasons.With the possibility of China rising as a?world power,Mandarin could definitely challenge the dominance of English as a global language.

Which language is now considered as the language of diplomacy?

A.French.
B.Chinese.
C.German.
D.English.