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                            These are the only two planets in our solar system without moons... 哪两个行星目前没有发现有卫星?
A: Mercury & Venus,  水星和金星
B: Venus & Mars,  金星和火星
C: Uranus & Neptune,  天王星和海王星
D: Neptune & Pluto, 海王星和冥王星
                            What is A: Mercury & Venus.  As far as we know, Saturn has the most moons.  Saturn has at least 25 satellites that measure at least 6 miles (10 kilometers) in diameter, and several smaller satellites. The largest of Saturn's satellites, Titan, has a diameter of about 3,200 miles (5,150 kilometers) -- larger than the planets Mercury and Pluto.