When can I use the expression "on second thoughts"?
Native speaker’s answer
Rebecca
"On second thoughts" (or much more commonly, "on second thought" in the singular form) is an informal expression used when you want to change a decision you've made or something you've just said. The speaker has used it in a humorous way here, as his previous statement implied that the book wasn't really worth buying. Ex: This tastes great! On second thought, never mind. It tastes like old mothballs. Ex: On second thought, I'll go with you to the mall after all! I want to get out of the house.