关于黄土高原水土流失的自然原因，叙述正确的是（ ）
①土质疏松②植被少③地形平坦④夏季降水集中⑤过垦过牧．
A：①②⑤
B：②③④
C：①②④
D：①③⑤
关于数字地球的叙述，不正确的是（ ）。
根据短文内容，选出一个最佳答案填入题前的括号内。
Name
Personal Information
Norman Bethune
Born in 1890 in Canada
A doctor
Came to China in1938
Died in 1939 in China
Celine Dion
Born in Montreal, Canada
A singing star
In 1997, sang My Heart Will Go On for the film Titanic
Thomas Edison
Born in 1847, Kentucky, USA
Made over 1,000 inventions
Died in 1931
Bill Gates
Born in 1955 in the USA
Wrote Business @ the Speed of Thought
Owns Microsoft Company
Mark Twain
Born in 1835 in the USA
A writer
Wrote the Adventure of Tom Sawyer
Died in 1910
