About three decades ago,   China was known as the “Bicycle Kingdom”. But the two­wheel way of transport's popularity began to fade, with many bikes soon replaced by their fuel­powered competitors.

But recent months have seen a revival of the bike across China, with an increasing number of people choosing to cycle   instead of driving to schools, to workplaces or to do sightseeing. The introduction of bike­sharing systems has brought the trend to   a new level.

People can unlock the shared bikes by simply using their smartphones. The bikes are equipped with GPS and can be left anywhere in public for the next user. They're popular among many Chinese people as they provide an effective solution to the “last mile problem”，   which refers to the final leg of a person's journey.

However, the systems have also led to problems such as   illegal parking, damage and theft. Last month, two nurses in   Beijing were placed under arrest for five days for putting locks on two shared bikes.

“Bike­sharing is a greener method of transport and provides a user­friendly experience，” said Liu Xiaoming, vice­minister of transport. “But it's a combination of online and offline business. Operators are usually strong in online services, but lack offline business experience, which causes problems.”

Now, Chinese service operators are trying to handle these problems. For example, a bike­sharing company called Mobike sets a 100­point credit score for each user, with points taken in the case of bad behavior. Once a score drops below 80, bike rental is increased to 100 yuan per 30 minutes, up from 0.5－1 yuan.

An old lady was walking with her basket down the middle of a street in Petrograd to the great confusion of the traffic and with no small danger to herself. It was pointed out to her that the pavement was the place for pedestrians, but she replied: “I’m going to walk where I like. We’ve got liberty now.” It did not occur to the dear old lady that if liberty entitled（授权）the pedestrian to walk down the middle of the road, then the end of such liberty would be universal chaos. Everybody would be getting in everybody else’s way and nobody would get anywhere. Individual liberty would have become social chaos.

There is a danger of the world getting liberty-drunk in these days like the old lady, and it is just as well to remind ourselves of what the rule of the road means .It means that in order that the liberties of all may be preserved, the liberties of everybody must be limited. When the policeman steps into the middle of the road and puts out his hand, he is the symbol not of tyranny（暴政）, but of liberty.

Liberty is not a personal affair only, but a social contract（契约）. In matters which do not touch anybody else’s liberty, of course, I may be as free as 1 like. If I go down the street dressed strangely, who shall say me no? We have a whole kingdom in which we rule alone and can do what we choose. But directly we step out of that kingdom, our personal liberty of action becomes qualified by other people’s liberty.

We all tend to forget this. A reasonable consideration for the rights or feelings of others is the base of social conduct.

Saying farewell to someone you love, even for a night, can be difficult, much less saying goodbye for a lifetime or forever in death. Juliet bid Romeo adieu (再见) for the evening with the words, “Parting is such sweet sorrow.” Sweet sorrow is an oxymoron. But this seeming contradiction is true in the context of relationships.

Relationships are based on feelings, emotions, and passion. Deep friendships and loving relationships are measured by the level of emotional attachment. Emotions intensify over time. People spend time with the people they like. The more one person likes another person, the closer the relationship becomes. Each person in the relationship receives an emotional benefit from knowing the other person.

Saying goodbye means separating from the people who make up a significant part of your emotional identity. Separation, even a temporary absence, from the people you have a deep emotional connection with can cause sorrow because you will no longer be able to enjoy their company.

The sweet side of saying goodbye is the emotional fulfillment of being in a close relationship. The time spent together is emotionally rewarding, especially if that person is seen as a soulmate. Humans are social beings. We seek the love and comfort of other people. Loneliness devastates the human condition and leads to sadness. Sad people will do anything they can to find fulfilling relationships. Likewise, happy people will do anything they can to maintain or enhance relationships. Herein lies the essential point of the emotional problem.

The more intense relationships become, the more devastating the emotional loss that is felt upon separation. The exhilaration of relationships cannot be truly measured without experiencing the overwhelming loss of a deep emotional connection.

Enjoy the company of the person you are with as long as you can; knowing the pain you will feel at the end of the relationship is the true measure of the relationship. If it doesn’t hurt to say goodbye, perhaps it wasn’t worth saying hello.