Pre - school can help close this gap. So in a speech last month, Mr. Obama called for a partnership between the federal government and the states to expand it to every American child. It later became known that "every" meant those who come from families with incomes of up to 200% above the poverty line - equal to an income of $47,000 for a family of four.

    Some critics say that sending children to school at the age of four does not work. The evidence suggests otherwise. For example, on March 20th new results were announced from a study of 9 - to - 11 - year - olds in New Jersey. This report found that disadvantaged children who had attended pre - school had better literacy (读写能力), language, maths and science skills. And two years of pre - kindergarten were better than one.

    Some studies also follow the effects of early learning over lifetimes, such as its effect on crime rates and other factors that may eventually burden society. Critics have singled out a government scheme called Head Start, created in 1965, which provides poor households with a range of services including school - based early education.

1.Kindergarten in rich countries other than America usually begins at the age of

    Humans may not have landed on Mars (火星) just yet, but that isn't stopping a European company from devising a plan to send four people to the Red Planet within the next few years. This project, called Mars One, aims to send a small group of people to Mars in 2022 and eventually establish a permanent colony on the planet.

    "Everything we need to go to Mars exists," said Mars One co - founder Bas Lansdorp in March 2014. "We have the rockets to send people to Mars, the equipment to land on Mars, the robots to prepare the settlement for humans. For a one - way mission, all the technology exists." Yet the four astronauts (宇航员) chosen for the trip will be stuck on Mars - forever.

    And despite Mars One's thorough planning, there are a number of challenges that may prevent the mission from ever taking place. The biggest road block could be the mission's huge cost ($6 billion). However, Lansdorp is confident that Mars One will be able to fund the project by selling the broadcast rights for the mission and subsequent experiences living on the planet.

    Those broadcast rights will also play a part in helping to select the people who will be sent to Mars. Lansdorp said the company will hold a selection process similar to a reality show. Lansdorp is expecting at least 1 million applications from people around the world. In addition to the cost, several other potential problems could inhibit (阻止) the mission to Mars.

    "It's even more challenging to send people there with life support, with food, with air, with all the other things like books, entertainment, means of communication and means of providing for their own resources for a long stay on Mars," said Adam Baker, senior lecturer in space engineering at Kingston University in London. "The sheer size of the rockets you'd need to do this would be absolutely colossal."

题目

According to Project Mars One, humans could send four people to Mars within the next _years.

When the United States Congress created Yellowstone National Park in  1872, the goal was to set aside a place where Americans could enjoy the  beauty of nature for years to come. Now, 142 years later, there are hundreds  of national parks across the country, and technology is changing the way  people experience them. Should park visitors be able to use cell phones,  or should their use be restricted?“Connectivity presents a real challenge to all of us.” Al Nash says.He is a public affairs officer at YellowstoneNational Park. He says cell  phone service at Yellowstone is available in parts of the park with stores  and campgrounds. This makes it easy for visitors to share photos of their  trip on social networking sites and to stay in touch with friends and family  members. If a park visitor is hurt or in danger, cell phones make it easier  to get help. Some say the ability to download applications that provide  information about plants and animals in the park can enrich a visitor’s experience.Others say cell phones disturb people’ s enjoyment of our national parks.  In their view, cell phone towers are an eyesore, and they’ d rather hear  the sound of birds than the ring of an incoming call. Can you imagine looking  out a peaceful lake or field of grass only to be disturbed by a person  shouting into their phone, “Can you hear me now?”Nash says Yellowstone tries to strike a balance. “Ultimately, our  job is to let visitors understand and enjoy nature better while protecting  what people find special about Yellowstone, and one of those things that's special is the ability to get away from the hustle and bustle(喧嚣)of one’ s daily life. ”

11. Which of the followings is the best title for the passage?