text: The author of the article described Venus as Earth's "twin." That suggests that we already know some facts about Venus such as it's density and size, which is enough to make people curious to how much about Venus we already know. He said that we know that Venus has many similar structures to Earth, such as mountains, valleys, and craters. If Venus is Earth's "twin," doesn't mean that it is extremely similar to Earth? The statement could make people curious about how close Venus really is to Earth, or it could make them wonder why we should bother risking people's safety if we already know that Venus is just like Earth. The author needed to be clearer on which way he wanted people to view that statement.