Er liest ein Buch.
I have one confusion sometime it says he is reading a book or he reads a book .Whats the difference of this in german in reading n reads ?
It is normal that you are confused with it because I was confused when I learned English.
The Difference is actually a question of time.The english Speakers have a language which is sometimes more precise at the timeline.
A german would agree on both being the right answer but a Scietist of the German Language would disagree that It makes no difference.You could translate he reads a book perfectly with "Er liest ein Buch" but on the other Hand if you say he is reading a book you would say something like "Er ist ein Buch lesen(d)".
The last form would Sound strange to a german like when Michael Fassbender orders 3 Beer with the wrong fingers in the movie and you would Sound like a foreigner with saying "Er ist ein Buch lesen(d)".
Be safe and say Er liest ein Buch.