What are the three air passages of the Mikuni carburetor?

Throat, throttle and choke. According to relevant public information, there is a throat channel inside the carburetor. Throttle passage and choke passage, and the passage through which air entering the engine flows. The carburetor consists of three parts: the upper part has an air inlet and a float chamber, the middle part has a throat, a metering hole and a nozzle, and the lower part has a throttle valve.