How many airlines are there? + Smile~

This is the picture I took from the Hong Kong International Airport few weeks ago. Can you tell me how many airplanes are there and how many airlines are there? Airline logos are printed mostly on the tail of an aircraft, it's like a flag flying in the wind, isn't it? Therefore the national airline, or the biggest and most important airline of a place is often called "Flag Carrier".

The picture above shows you Cathay Pacific's Airbus 340-300. How do I know the model of the aircraft? It's easy to tell. For Cathay Pacific, if you see four engines without a "goose hump" (the one with the "goose hump" is Boeing 747), that is an Airbus 340. And if you can see only 4 doors on the aircraft, instead of 5, that is Airbus 340-300 instead of Airbus 340-600.

And you can see the side cargo door is open, they need this big door to load the big cargos into the airplane.

I took this picture in Shanghai Science Museum. And it was a tank of orange fish. I happened to see one of them facing me and it looked as if it was smiling at me. Isn't it cute? I hope to see you smiling at me like this when I see you in the school.