The TED speaker series features “ideas worth spreading.” With over 1,400 to choose from, we’ve selected a few that are perfect for students.

We humans have an excellent ability to make excuses for ourselves. Larry Smith, a professor of economics at the University of Waterloo in Canada, tells us why most of us will fail to have a great career. But there is a way out— if you try to pursue your passion.

Between dance team, volunteering and—oh, right—lectures, your life’s crazy factor is about to go way up. In this entertaining and informative talk, mindfulness expert Andy Puddicombe teaches us how to be “more healthy, more mindful and less distracted” by taking just 10 minutes out of the day to be more present.

This talk is sure to stay with you. Shane Koyczan’s “To this DAY” is an affecting spoken-word poem about bullying and being different that gained over 10 million views on YouTube. In this talk, Koyczan gives a live reading of the poem, along with some stories about his background.

Does a cup of tea and a good book sound like a perfect Friday night? In this personal talk, Susan Cain argues that introverts have important talents and abilities. Our culture may value being social and outgoing, but the world needs all kinds.

In spite of “endless talk of difference”, American society is an amazing machine for homogenizing people. This includes the uniformity in clothing and communication, as well as the casualness and lack of respect seen in popular culture. People are absorbed into “a culture of consumption” launched by the 19th-century department stores that offered a wide range of goods in an elegant atmosphere. Instead of fancy shops catering to the upper-class, these were stores “anyone could enter, regardless of class or background.” This turned shopping into a public and democratic (民主的) act. The mass media, advertising and sports are other forces for homogenization.

Immigrants are quickly adapting to this common culture, which may not be altogether elevating but is hardly poisonous. Writing for the National Immigration Forum, Gregory Rodriguez reports that today’s immigration is neither at remarkable levels nor resistant to assimilation (融合). In 1998 immigrants were 9.8 percent of population; in 1900, 13.6 percent. In the 10 years prior to 1990, 3.1 immigrants arrived for every 1,000 residents; in the 10 years prior to 1890, 9.2 for every 1,000. Now, consider three indicators of assimilation — language, home ownership and intermarriage.

The 1990 Census revealed that “a majority of immigrants from each of the fifteen most common countries of origin spoke English ‘well’ or ‘very well’ after ten years of residence.” The children of immigrants tend to be bilingual (双语的) and good at English. “By the third generation, the original language is lost in the majority of immigrant families.” Hence, America is described as a “graveyard” for languages. By 1996 foreign-born immigrants who had arrived before 1970 had a home ownership rate of 75.6 percent, higher than the 69.8 percent rate among native-born Americans. Foreign-born Asians and Hispanics “have higher rates of intermarriage than do U.S.-born whites and blacks.” By the third generation, one third of Hispanic women are married to non-Hispanics, and 41 percent of Asian-American women are married to non-Asians.

Rodriguez notes that children in remote villages around the world are fans of superstars like Arnold Schwarzenegger and Garth Brooks, yet “some Americans fear that immigrants living within the United States are not influenced by the nation’s assimilative power.”

Are there divisive issues and anger in America? Indeed. It is big enough to have a bit of everything. But particularly when viewed against America’s troubled past, today’s social Indicators hardly suggest a dark and worsening social environment.

English is full of funny expressions that don’t always make sense. What do they mean? How do we use them? And where did they come from? Idioms are phrases and sentences that do not mean exactly what they say. Even if you know the meaning of each word you see or hear, you may not understand the idiom because you don’t understand the culture behind it. Here are some English idioms based on animals.

When children jump around and act silly, for example, their parents may tell them to stop “monkeying around”. To “monkey around” means to do things that are not useful or serious, or to simply waste time.

But spending time playing with their family pets wouldn’t count as “monkeying around”. Many American families have a pet dog, which keeps the children company and makes them happy. Bu for some reason, which American language experts do not know, Americans use “dog” in a phrase that means to feel unwell. If you are “as sick as a dog”, you’re really, really sick and will have to stay home and rest or even go and see a doctor.

Apart from dogs, cats are also beloved in U.S. households. Sometimes you may hear them mentioned in Americans’ conversations, “I told you to keep that secret, but you have just ‘let the cat out of the bag’!” You probably guessed it — that idiom means to reveal a secret or tell facts that were previously unknown.

Dogs and cats don’t always get along, but they appear side by side in a commonly used idiom. When it rains heavily, people might say it’s “raining cats and dogs” outside.

Bad weather often ruins people’s plans for outdoor activities. But on a lovely day, they can go on an outing or have a picnic in the park. If a swarm of tiny bugs decide they love your picnic food and start to hover (盘旋) around you and your friends, then it would be really annoying, wouldn’t it? That experience perfectly explains why people often tell someone who keeps bothering them to “stop bugging me”.

Idioms are very common in both spoken and written English, so learning them is very important. If you need to understand English, or if you want to speak or write natural-sounding English, you have to learn idioms.