As you can see in the following list, there is a rainbow of colors in the sky represented by the planets.

Planet	Color
Mercury （水星）	Orange
Venus（金星） 0）	Yellow
Earth	Blue, brown, green
Mars	Red
Jupiter （木星）	Yellow, red, brown, white
Saturn  （土星）	Yellow
Uranus （天王星）	Green
Neptune （海王星）	Blue
Pluto（冥王星）	Yellow

 
The color of a star is an indication (标示) of its brightness, temperature, and age. Stars are classified into groups. From oldest to youngest and from hottest to coolest, the types of stars are:

		Temperature
Type	Color	Fahrenheit	Celsius
O	Blue	45,000-75,000	25,000-40,000
B	Blue	20,800-45,000	11,000-20,000
A	Blue-white	13,500-20,000	7,500-11,000
F	White	10,800-13,500	6,000-7,500
G	Yellow	9,000-10,800	5,000-6,000
K	Orange	6,300-9,000	3,500-5,000
M	Red	5,400-6,300	3,000-3,500

 
Jupiter, Saturn, Uranus, and Neptune all have rings. Jupiter's rings were discovered by Voyager 1 in March 1979. The rings extend 80,240 miles from the center of the planet. They are about 4,300 miles wide and less than 20 miles thick.
Saturn has the largest, most wonderful rings in the solar system. Saturn's rings are about 41,168 miles wide and 169,800 miles in diameter, but less than 10 miles thick.
In 1977, when Uranus passed in front of a star, scientists found that the light from the star winked several times before the planet totally blocked the star from view. It was due to the rings around Uranus. The rings are thin, narrow, and very dark.
Voyager 2 discovered a series of at least five very faint rings around Neptune in 1989. The rings are made up of particles, some of which are greater than one mile in diameter.
A day, the period of time it takes a planet to make one complete turn, varies from planet to planet. A day on Venus, Mercury, and Pluto is several times longer than a day on Earth. A Martian day is closest in length to our own. The rest of the planets have shorter days than we do.
Length of Day

Planet	Earth Days	Hours	Minutes
Mercury	58	15	30
Venus	243		32
Earth		23	56
Mars		24	37
Jupiter		9	50
Saturn		10	39
Uranus		17	14
Neptune		16	3
Pluto	6	9	18

Among the nine planets, how many may show yellow color?
A. Four.            B. Five.           C Six.          D. Seven.
What is the type of Mars?
A. Type A.         B.Type F.          C. Type K.       D. Type M.
Whose rings are made up of particles around one mile in diameter?

A．Jupiter's.

B．Saturn's.

C．Neptune's.

D．Uranus's.

How long is a day on Mars?

A．Fifteen hours and thirty minutes.

B．Seventeen hours and fourteen minutes.

C．Twenty-three hours and fifty-six minutes.

D．Twenty-four hours and thirty-seven minutes.