CPU tempreture is high

After installing Ubuntu 18, I found that cpu fans are working all the time no matter how I use the computer.
I could have see the temperature of the CPU with "sensors".

To install "sensors" on Ubuntu 18:

• "sudo apt install lm-sensors hddtemp"
• Then to start the detector, you run "sudo sensors-detect"
• Finally the command for seeing cpu temperature is "sensors"