【推荐1】Mesopotamia was home to some of the very first cities in existence, leading many to link it to the birth of civilization. The origin of these cities is still unknown today, although many theories exist. One suggestion is that the development and building of temples created a place where people would gather, and thus served as points of contact between different groups of people.

Others believe that people sought sanctuary from natural disasters. As the Mesopotamians were able to develop technology to help them control the nearby rivers, such as levees, they could ensure a good crop. They had no need to be nomadic, and were able to settle in one place comfortably. It is for this reason that all the early cities were built along the two major rivers.

From the moment the Sumerians began to form these cities, it forever altered human history. People went from being ruled by nature, to attempting to control it and make it work for them. By 4,500 BCE the first recorded city rose in the form of Uruk. However, the only urban structure at this point was the temple, which regulated all economic and social matters.

The central purpose of these early cities was to help regulate trade, as southern Mesopotamia was reliable on outside resources. This need encouraged the spread of urbanization. However, communication between the cities was difficult, so each city developed into an individual city-state. This led to territorial disputes and, inevitably, war.

In order to keep their cities protected, the Mesopotamians built fortifications, and walled cities rose. Migration to these cities increased, and more buildings were erected. Cities gradually expanded and rulers were proclaimed, who then began looking outwards for trade and conquest.

【推荐3】Managers across nearly every industry believe distraction soars as the temperature rises.     1    . More than anything, our environment impacts our productivity

    2    . Think about your morning commute: It’s sticky and humid even at 8 a. m., and by the time you get into your air-conditioned office, you’re already exhausted. Heat causes many people to feel lethargic, making it much more difficult to focus on that meeting you have first thing.

Sure, people travel and do other fun activities year-round, but many people have more going on between May and September than they do any other period.     3    . “Even if you’re not taking an exciting vacation, perhaps your coworkers are out of the office a lot,” Schinke says. “This can impact the productivity of the whole team.”

    4    . The sun won’t set until past 8 p. m., so it’s natural to want to soak up every moment after you escape your overly air-conditioned office.

During these months, you’re far more likely to stay up later, meaning you feel sleepy when it’s time to clock in. It’s not too different than the decline in productivity that follows the Super Bowl or St. Patrick’s Day.     5    .

【推荐2】Today, Mars is a frozen desert with a thin atmosphere, too cold for liquid water to remain on the surface. Overwhelming evidence exists that Mars had liquid water oceans roughly 4 billion years ago. The question that drives our interests isn’t whether there’s life on present-day Mars. We are driven instead by asking whether there was life on Mars billions of years ago, which seems significantly more likely.

But if water existed on the Marian surface before, how was it possible? Mars is further away from the sun than Earth, and billions of years ago, the sun didn’t throw off as much heat as it does now.

The planet’s protective magnetic field mysteriously disappeared around 4.2 billion years ago as Mars cooled after forming. The sun’s solar wind then blew away the Martian atmosphere. leaving behind the thin one the planet has today.

Scientists believe the atmosphere was a key component for a warm, wet Mars that may have once hosted life. To have made the planet warm enough for liquid surface water, its atmosphere would likely have needed a large amount of greenhouse gas, carbon dioxide specifically.

Currently, we don’t know the carbon dioxide content of Mars ancient atmosphere. So the researchers turned to the Nordlinger Ries crater（陨石坑）in southern Germany. It was created by a meteorite（陨石）impact 15 million years ago. That geology and the chemistry of the site act as a good similar for the Martian surface.

Researchers will study the pH and nitrogen that might have been in ancient Martian water, which will show the carbon dioxide content in its ancient atmosphere. That will throw light on whether Mars was once warm enough to support life.

The Mars 2020 rover（探测器）will land in a similar crater next year, collecting samples that will be returned to Earth in a future mission. It could be 10 to 20 years before Mars samples are brought back to Earth. We might know the answer to one of the first questions once these samples are distributed to labs in the US and throughout the world.

【推荐3】In the journey of life, there’s an often ignored hero — labor. Yes, that’s right, good old-fashioned hard work. Whether it’s mowing lawns, babysitting, or washing dishes, the act of laboring not only fills pockets but also shapes characters and molds futures.

Let’s face it, we live in a world where instant satisfaction is the norm (标准). But what if we told you that delaying that satisfaction and putting in some good, honest sweat can actually be beneficial? It’s true!     1    

    2     Imagine a teenager tasked with mowing lawns for a summer job. Suddenly, they’re responsible for showing up on time, doing a thorough job, and managing their earnings. These are life skills that no classroom lecture can match.

Moreover, labor breeds (培养) perseverance.     3     Instead of throwing in the towel, they persevere, learning from each setback and growing stronger in the process. This perseverance becomes a cornerstone (基石) for success in all aspects of life.

But perhaps the most profound impact of labor is its ability to foster empathy and appreciation.     4     As teenagers serve meals to the less fortunate, they gain a newfound perspective on privilege and gratitude. Suddenly, that new smartphone doesn’t seem as important as lending a helping hand to those in need.

In conclusion, labor isn’t just about earning a paycheck but it’s also about shaping character and building a foundation for success. So, the next time you see a teenager sweating it out on a hot summer day, remember —     5