YOU SAID:

This is a great source of procrastination

INTO JAPANESE

これは先延ばしの大きな原因です

BACK INTO ENGLISH

This is a major cause of procrastination

INTO JAPANESE

これは先延ばしの主な原因です

BACK INTO ENGLISH

This is the main cause of procrastination

INTO JAPANESE

これが先延ばしの主な原因です

BACK INTO ENGLISH

This is the main cause of procrastination