What's the difference between 最近、このごろ and 近頃?

Question

I always thought that they had similar meanings, however I got an exercise where I got all 3 of them and one only is the right choice.

Answer 1

I will skip the explanation of the more superficial differences in meaning among these words because @WKx has already done it.

Instead, I am going to explain a rather important "hidden" difference in usage that would not be apparent if one just "translated" these words into English. After all, the three words all mean along the lines of "recently".

「[最近]{さいきん}」 is the most versatile of the trio in that it can be used to talk about all of the following phenomena:

1. Continuous or repetitive actions/events.

「ほとんど[毎日雨]{まいにちあめ}が[降]{ふ}っています。」= "It has been raining almost everyday."

「よく[運動]{うんどう}しています。」= "I have been exercising a lot."

2. States and situations.

「ペドロは[病気]{びょうき}で、ほとんど[学校]{がっこう}にも[来]{き}ていません。」= "Pedro is sick and has been mostly absent from school."

3. One-time-only or momentary actions/events.

「スミスさんはディズニーランドに[行]{い}きました。」= "Mr. Smith went to Disneyland."

「～～という[本]{ほん}を[読]{よ}みました。」= "I read a book called '~~~'."

「マサコさんはビールを1ガロン[飲]{の}んでしまった。」= "Masako drank a gallon of beer."

「このごろ」 and 「[近頃]{ちかごろ}」, however, can only be used to talk about the first two above. Careful speakers and writers would not use these words to talk about one-time-only or momentary events.

For instance, if you want to talk about reading a particular book, you can only use 「最近」, not the other two words, but if you are talking about any books (e.g., how many books per week you have been reading recently), you can use any of the three words in question.

Answer 2

First, most of the time they would mean the exact same thing : ~lately/recently, and can be interchanged.

However there can be different feeling in the nuance of how long before you are referring to. By order of most recent to most distant :

このごろ > 近頃 > 最近

このごろ is something that happened recently and still continuing or the result is impacting the present.

最近 can basically refer to how long ago you wish without sounding strange, for example "compared to the age of the universe, the human are on earth only recently", this recently can only be 最近

Also, このごろ is a very speech-like expression, and you would rarely see it in written composition.