I have heard that ; but I'm unsure that it is true.
the lectionary is on a three-year cycle: A, B, C
Why would you be “unsure that it is true”?
Have you gone to Mass every Sunday for 3 years to find out?
The Sunday Masses are in a three year cycle—years A,B, and C, . In addition, in the daily Masses, the Scriptures are in a 2-year cycle—Year I and Year II. The Sacred Scriptures, in the 3-year Sunday cycles and the 2-year daily cycles, are thoroughly covered.
In addition, the readings of the Sunday Masses and the daily Masses are matched thematically. They are not loosely thrown together. For this reason, many Catholics are often very familiar with Scriptural texts and phrases, not any more by chapter and verse, than also by similarity of theme.
I think it's important to make clear that, by attending every Mass offered in 3 years, one hears the entire Bible, and it's interpretation by a priest. IOW, going to Sunday Masses only will not give one the entire Bible; one must attend every Daily Mass as well.