[填空题]

Reinventing the Table

An earth scientist has rejigged the periodic table to make chemistry simpler to teach to students.
(46) But Bruce Railsback from the University of Georgia says he is the first to create a table that breaks with tradition and shows the ions of each element rather than just the elements themselves.
"I got tired of breaking my arms trying to explain the periodic table to earth students," he says, criss-crossing his hands in the air and pointing to different bits of a traditional table. (47) But he has added contour lines to charge density, helping to explain which ions react with which.
"Geochemists just want an intuitive sense of what’s going on with the elements," says Albert Galy from the University of Cambridge (48)
(49) He explains that sulphur, for example, shows up in three different spots one-for sulphide, which is found in minerals, one for sulphite, and o

[填空题]
An earth scientist has rejigged the periodic table to make chemistry simpler to teach to students.
(46) But Bruce Railsback from the University of Georgia says he is the first to create a table that breaks with tradition and shows the ions of each element rather than just the elements themselves.
"I got tired of breaking my arms trying to explain the periodic table to earth students," he says, criss-crossing his hands in the air and pointing to different bits of a traditional table. (47) But he has added contour lines to charge density, helping to explain which ions react with which.
"Geochemists just want an intuitive sense of what’s going on with the elements," says Albert Galy from the University of Cambridge (48)
(49) He explains that sulphur, for example, shows up in three different spots one-for sulphide, which is found in minerals, one for sulphite, and o

[填空题]
An earth scientist has rejigged the periodic table to make chemistry simpler to teach to students.
(1) But Bruce Railsback from the University of Georgia says he is the first to create a table that breaks with tradition and shows the ions of each element rather than just the elements themselves.
"I got tired of breaking my arms trying to explain the periodic table to earth students, " he says, criss-crossing his hands in the air and pointing to different bits of a traditional table.
(2) But he has added contour lines to charge density, helping to explain which ions react with which.
"Geochemists just want an intuitive sense of what’s going on with the elements, " says Albert Galy from the University of Cambridge, (3)
(4) He explains that sulphur, for example, shows up in three different spots — one for sulphide, which is found in mineral

[单项选择]First designated in 1970, Earth Day has become an annual international event ______ concerns about environmental issues such as pollution.
A. dedicated to raising
B. dedicated raising
C. dedicates to raise
D. that dedicates to raising

[单项选择]

Escaping from the Earth
The Earth has a force that pulls things toward itself. We call this force gravity(地心引力). This is something we live with all the time, and we take it for granted and hardly ever think about it. But it is a most important factor in rocket operation and must be overcome if we are to get anywhere in space, or off the ground at all.
Take the throwing of a hall as an example. The harder the ball is thrown, the faster and higher it will go. What is the secret Its speed. If we could throw the ball hard enough it would go up and up forever and never come down. The speed at which it would have to be thrown to do this is known as escape speed. Of course, we cannot throw a ball hard enough because the speed required to escape completely from the Earth’s gravity is seven miles per second, or over twenty-five thousand miles per hour.
Once escape speed has been reached by a spacecraft(宇宙飞船), no further power is needed. A rocket aimed
A. Few spacecrafts complete their flight operations.
B. The Earth’s gravity cannot be overcome.
C. No future power is needed after the escape speed is reached.
D. "Free fall" takes the place of the Earth’s gravity pull.