“Lying on a beach is much more pleasant than sitting in an office” You use “lying” and “sitting” because you’re talking about the abstract concepts of doing those things. All of the times you can imagine lying on a beach are better than all the times you imagine sitting in an office. Note that you’re comparing to “sitting in an office” in the abstract, not only your particular office today. “To lie on the beach is much more pleasant than to sit in this office.” Now you are comparing one singular time to another. Once you were on the beach, and now you are in the office, and comparing the memories the beach was nicer. Note that here you’re comparing to “this office” because you’re there now.

hi southblue, think both C) Lying/ sitting & D) To lie/ to sit are perfectly okay. here's the rule: if you're comparing a word, a clause or a phrase, you should observe a parallel structure or verb pattern: not parallel: "hiking is better than to swim." parallel: "hiking is better than swimming." not parallel: "to forgive is forgetting." parallel: "to forgive is to forget." as far as I know, you can use "to" before all the verbs in a sentence or only before the first one. " I like to lie on a beach much more than to sit in this office." :)

c)lying, sitting