For most of the 20th century, the solution to the mystery of the original Americans-- where did they come from, when, and how?--seemed as clear as the geography of the Bering Strait, the climate of the last ice age, and the ubiquity of finely wrought stone hunting weapons known as Clovis points.

According to the ruling theory, bands of big-game hunters trekked out of Siberia sometime before 11,500 years ago. They crossed into Alaska when the floor of the Bering Strait, drained dry by the accumulation of water in a frozen world's massive glaciers, was a land bridge between continents, and found themselves in a trackless continent, the New World when it was truly new.

The hunters, so the story went, moved south through a corridor between glaciers and soon flourished on the Great Plains and in the Southwest of what is now the United States, their presence widely marked by distinctive stone projectile points first discovered near the town of Clovis, New Mexico. In less than 1,000 years, these Clovis people and their distinctive stone points made it all the way to the tip of South America. They were presumably the founding population of today's American Indians.

Now a growing body of intriguing evidence is telling a much different story. From Alaska to Brazil and southern Chile, artifacts and skeletons are forcing archaeologists to abandon Clovis orthodoxy and come to terms with a more complex picture of earliest American settlement. People may have arrived thousands to tens of thousands of years sooner, in many waves of migration and by a number of routes. Their ancestry may not have been only Asian. Some of the migrations may have originated in Australia or Europe.

1. What is the main idea of this passage?

2. In this passage, trekked means

3. In this passage, presumably means

4. The passage states that the Clovis people came to North America from

5. The Clovis people are named after the place where

6. Scientists now believe that Native Americans originally came from

7. The author's purpose in writing this passage was to

8. The Clovis people are best known for the type of

I Build Walls

:I build walls
,Walls that protect
,Walls that shield
,Walls that say I shall not yield
Or reveal
.Who I am or how I feel

:I build walls
,Walls that hide
,Walls that cover what’s inside
,Walls that stare or smile or look away
,Silent lies
Walls that even block my eyes
.From the tears I might have cried

:I build walls
Walls that never let me
Truly touch
.Those I love so very much
!Walls that need to fall
Walls meant to be fortresses
.Are prisons after all

• In this poem, walls are not made of bricks or any physical materials. The author uses “walls” as a metaphor for someone hiding his feelings and thoughts from others and even from himself.
• ?Why would someone build “walls” around his or her feelings
• ?Do you, or others you know, ever build such “walls”
• ?Does the narrator believe that it’s always a good idea to have these “walls”? How do you know?

Space Exploration
From Wikipedia, the free encyclopedia

Space exploration is the physical exploration of outer space, both by human spaceflights and by robotic spacecraft. While the observation of objects in space—known as astronomy—pre-dates reliable recorded history, it was the development of large liquid-fueled rocket engines during the early 20th century that allowed space exploration to become a practical possibility. Common rationales for exploring space include advancing scientific research, uniting different nations and ensuring the future survival of humanity.

Space exploration has often been used as a proxy competition for geopolitical rivalries such as the Cold War. The early era of space exploration was driven by a "Space Race" between the Soviet Union and the United States; the launch of the first man-made object to orbit the Earth, the USSR's Sputnik 1, on October 4, 1957, and the first Moon landing by the American Apollo 11 craft on July 20, 1969 are often taken as the boundaries for this initial period. The Soviet Union achieved many of the first milestones, including putting the first man in space, Yuri Gagarin aboard Vostok 1 in 1961, and completing the first spacewalk (by Aleksei Leonov in 1965). In 1971, the Soviets launched the first space station, Salyut 1.

After the first 20 years of exploration, focus shifted from one-off flights to renewable hardware, such as the Space Shuttle program, and from competition to cooperation as with the International Space Station. From the 1990s onwards, private interests began promoting space tourism. Larger government programs have advocated manned missions to the Moon and possibly Mars sometime after 2010.

Various criticisms of Space Exploration are sometimes made, on cost or safety grounds, but the people of many countries are nevertheless usually supportive of programs.