阅读下面短文，从所给选项中选出能填入空白处的最佳选项，使短文通顺，结构完整，其中有一项是多余选项。

The Moon is a natural satellite that moves around the Earth. 【小题1】 It is much smaller than the Earth, and it takes about 27 days for it to complete one orbit around our planet.

【小题2】 The Moon appears differently throughout the month because of its phases (月相). Sometimes it looks like a big round ball, and other times it appears as a thin crescent. These changes in appearance are caused by the Moon’s position relative to the Sun and the Earth.

The Moon’s surface is covered with craters (环形山), which are big round pits. 【小题3】Some craters are really big, like the one called the Copernicus crater, which is about 93 kilometres wide.

Do you know that humans have actually visited the Moon? In 1969, the Apollo 11 mission landed astronauts Neil Armstrong and Buzz Aldrin on the Moon’s surface. 【小题4】 Since then, a total of six Apollo missions have landed astronauts on the Moon, and they brought back samples of Moon rocks to study on the Earth.

【小题5】 It has an influence on the tides of our oceans. It also provides a natural satellite for us to study and explore. Scientists continue to learn more about the Moon’s geology, history and potential (可能性) for future exploration.

A．It is our closest neighbour in space.

B．The Moon plays an important role in our lives.

C．Do you know how many satellites the Earth has?

D．They were the first humans to set foot on the Moon.

E．Have you ever noticed that the Moon changes its shape?

F．These craters were formed by asteroids (小行星) and meteoroids (流星体) crashing into the Moon’s surface.