Thank you for the help, mdchachi. I made a mistake. Sorry. I know you don't say "I listens to the radio." For some reason your link does not work. I think you can say "hardly" and "scarcely" are synonyms and "rarely" and "seldom" are also synonyms but rarely or seldom is a little different from hardly or scarcely.
How about this one? (e) I _____ know about your country. I guess you can put "hardly" but not "rarely", "seldom" or "hardly ever". Am I right?
Strange. It works for me. Anyway here is the text:
What is the difference between "hardly' and hardly ever"?
Best Answer: "Hardly" refers to amount or degree and it means "almost not." "Hardly ever" refers to frequency and it means "almost never." You can often use "hardly" to replace "hardly ever." You usually cannot use "hardly ever" to replace "hardly." Look at the examples and notice the difference. Try to substitute them and see if it works.
A: How much did you study for your exam? B: I hardly studied. (I studied for just a few minutes.)
A: How often did you study for your exams in college? B: I hardly ever studied in college. (I rarely studied for any of my exams in college.)
A: I'm so hungry! B: Well, you've hardly eaten today. (You haven't eaten much today.)
A: I'm so fat! B: No, you're not! You hardly ever eat! (You don't eat often.)