Venus (金星) is close to Earth. 【小题1】   Earth is the third planet from the Sun. Venus is similar to Earth in size and mass (质量). It is often described as Earth’s “sister”.

Scientists have been learning about Venus for a long time. First, they looked at Venus through telescopes (望远镜). But Venus is covered with thick clouds. 【小题2】 So, they made guesses about it.

For a long time, scientists thought that Venus had water and plants. They thought Venus might have animals, too. 【小题3】

【小题4】 In the 1960s, they began sending probes (航天探测器) to Venus. The probes flew through the thick clouds. They took pictures of Venus up close. They found out many things, too. The probes sent the pictures and things they found out back to the scientists.

【小题5】 First, they learned that most of their guesses were not right. And they learned that Venus is very hot.