Hi,
I remember hearing from someone that “etc” and “so on” shouldn’t be used in formal writing. Is this idea right or wrong? And if it is right, then which word should be used in these cases when we need to express that idea?
Many thanks in advance
Nessie 
This is absolutely correct. There is no “magic word” that works as a substitute, largely because the reader should not be left to guess what might or might not be on your list. If you are absolutely forced into a sentence where you want to use “etc.,” my suggestion would be to recast the sentence to say something like “Examples include A, B, and C.”
I hope this helps!
Rick
Hi Rick,
Thanks a lot for your help, but could you please be a little bit more specific about your suggestion? I still wonder what we can use in such cases…
Example:
I would use lots of bright colors, such as lemon yellows and neon blues, in this room. (Using “such as” instead of e.g., or etc.)
Many of America’s finest authors, including Hemingway and Fitzgerald, wrote about their personal experiences. (using “including” instead of e.g., or etc.)
I hope this helps.
Rick
Er… I’m not very sure about that, Rick.
Thank you very much for your help but I don’t really mean that. Please have a look at this sentence:
Everyday she has to do a lot of things such as cleaning the house, cooking the meals, collecting the children, etc/ and so on.
=> In the above sentence, if we can’t use “etc” or “so on”, then what should we use to fully express the idea?
I would write “such as cleaning the house, cooking, the meals, and collecting the children.” The use of “such as” tells the reader you are not making a complete list, and the reader will know that she has other similar tasks to do. The words “such as,” in other words, means exactly the same things as “etc.” and “and so on.”
That’s exactly what I want to state, Rick. What if I want to make an incomplete list? what can I use?
Sorry but I don’t think “such as” mean exactly the same as “etc” and “so on”…
I am terribly sorry to disagree with you, but as a native English speaker with seven years of college and a degree in law, and as a teacher of English, I have to insist that my use of the language here is correct, and that there is no significant difference between “etc.” and the phrasing I provided. Please take it to another native English speaker who teaches English if you want a second opinion.
If you are looking for another turn of phrase, you could use the legalistic and wordy ''including but not limited to" phrase that lawyers often put in contracts to express the idea that the list of items mentioned is nonexhaustive.
Have you looked up the meaning of “such as” and “etc.” in a dictionary? I think you will see that you are in error.
Regards,
Rick
Hi Rick,
I don’t ever mean not to believe you. I just stated my idea 
And I’m very grateful for your enthusiastic help
Many many thanks once again
Nessie