#3 works best for me.
1) I have learned gerunds.
2) I have learned about gerunds.
3) I have learned how to use gerunds.
I thought I had known well about usage of "about" but all of a sudden, I was wondering if there is a meaning difference between them and which one is appropriate or natural to you? Merry Christmas and I am not in a hurry, so enjoy your holidays and when you are free and convenient, please, help me outThank you so much as usual.
#3 works best for me.
Thank you so much as usual and I also thought that "I have learned / learned about gerunds." is somewhat weird, but it seems like people also say them. Don't you think so? Or usually native English speakers do not use the construction. especially with "terms like gerunds"?
You could learn about gerunds without learning how to use them.
Remember - correct capitalisation, punctuation and spacing make posts much easier to read.