If you are asking if the moon is the only moon that can eclipse the sun, then the answer is yes. We only have one moon. The planets Mercury and Venus pass beween the earth and the moon but are much further away from the earth than the moon. Because of their small size (due to distance) they are not able to block out the sun.
An eclipse of the sun can only occur during a New Moon. A New Moon is when the moon passes between the earth and the sun. We usually have a solar eclipse about twice a year. The total phase of a solar eclipse is very short, but beautiful. Surrounding the black disc you can witness the sun's solar corona, which looks like a wispy halo of light. You should never look directly at a solar eclipse because the light can hurt your eyes.
There are four types of solar eclipses:
- Partial-when the moon passes in front of the sun but does not cover it
- Total-when the moon covers the sun completely
- Annular-if the moon is further away from the earth than normal than it will not appear large enough in the sky to cover the sun
- Hybrid-when the eclipse appears as a total eclipse in some parts of the world and as an annular eclipse in other parts.