Tanzania（坦桑尼亚）is a country which has a lot of animals, such as gnus（角马）, lions, cheetahs（猎豹, elephants, giraffes, crocodiles and so on. Every year, many people in the world travel to this African country to watch the animals closely. But do you know how they travel?

    By bus—This is the most common way. When people get on a bus, they'll find that the bus is a little strange. It is different from the buses we often see. There are no big windows at all, but some small windows. And it looks like a cage. What are they used for? Oh, people can use it to watch animals, especially those dangerous animals, and take photos. We know that people are most interested in the lions. So when two buses meet, the drivers will stop and ask each other whether they have found lions.

    By boat—We can often see many people are in a boat, enjoying the beautiful scene along a river of a lake, and they can also enjoy hippos（河马）and crocodiles from a nearer distance.

    By hot balloon（热气球）—In the early morning, when the sun is beginning to rise, a large hot balloon is also starting its journey. Taking a hot balloon makes most of the travelers excited. After some time, the balloon will land in a certain place, and the waiters will serve people a delicious and special breakfast. But the cost of taking a hot balloon is also very high. A person should pay 400 dollars for an hour's trip.

“商品—货币—商品”，这个公式说明（    ）

①在商品流通中货币充当商品交换的媒介

②买和卖两种行为在同一时间和空间中进行

③货币具有流通手段的职能

④货币具有价值尺度的职能

掷一枚质地均匀的骰子，六个面上分别标有1，2，3，4，5，6；则出现点数为1的概率为​____ .