Choose the idiom/phrase that can substitute the highlighted group of words meaningfully.
Stop preaching. You must understand that it is tougher to do something in reality than to say or think.
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. Easier said than done.
The idiom "easier said than done" means that it is easy to talk about doing something, but much more difficult to actually do it in reality.
This fits the context where the speaker is emphasizing the difficulty of putting words or thoughts into action.