Europeans are being dug out from heavy snow after a week of very cold weather. The snowstorm is the harshest to hit Europe. Airports were shut down. And schools have been closed for a week.
    Until Wednesday, at least 400 people across Europe had died because of the cold temperature. Several countries have said a state of emergency. In Ukraine, temperatures dropped as low as -33℉.
    Although the situation is bad, at least one country is hoping the weather will last a little longer. In the Netherlands, the government is preparing for the country’s “11 Cities Tour”. The 125-mile ice-skating marathon will be held along a network which joins 11 towns and cities together in Friesland Province.
    The ice along the way must be inches thick for the event. Up to 2 million people are thought to cheer on the race's 16,000 competitors.
On Wednesday, Dutch soldiers joined in the preparations. They cleaned snow along the way. This will be the 16^th time that the event has taken place since the first race in 1909. Dutch General Hans said his soldiers were happy to lend a hand. “We want to do our bit for this national party.” he said.

如下图所示，正常使用时属于费力杠杆的是（   ）

设函数y=f(x)在(-∞,+∞)内有定义，对于给定的正数k，定义函数：$f_k\left(x\right)=\left\{\begin{array}{c}f\left(x\right),\left(f\right(x)\le k)\\ k,\left(f\right(x)>k)\end{array}\right.$,取函数f(x)=2-x-e^-x，若对任意的x∈(-∞,+ ∞)，恒有f_k(x)＝f(x)，则(    )