1) A.M. and P.M.
2) B.C.E. and C.E.
3) i.e. and e.g.
4) Scuba
So how'd you do? If you knew them all, then you are more qualified to answer questions from a three-year-old than I am. Or maybe you were like me: a little hazy on the full phrasing for some of those. ( "Scuba! I know this one! Submersible . . . c-something . . . underwater breathing apparatus? Maybe? Wait, lemme Google it.*") If that was you, allow me to save you some Googling.
Answers after a totally unrelated photo of Charlie wrecking the joint:
1) AM and PM=ante meridiem and post meridiem. I thought it was meridian, but that's just the line of longitude on a globe. Meridiem is a Latin word for midday. Good to know.
2) B.C.E. and C.E.=Before Common Era and Common Era. I did know this one, although this is the more recent way of referring to years and I still sometimes expect to see the old B.C. and A.D. I learned as a kid. Because I am ancient, apparently.
3) i.e. and e.g.=i.e. stands for the Latin words "id est" (which kind of means "in other words") and e.g. stands for the Latin words "exempli gratia" (roughly "for example"). Good luck explaining the differences in grammar usage to a three-year-old who thinks "comfortabler" (as in "more comfortable") is a word.
4) Scuba=Self-contained underwater breathing apparatus. I got three of the five words there. Is that a passing grade?
Thank God for the Internet. It allows me to appear a lot smarter to my preschooler than I apparently am.
* Or if A. is handy, just ask him, since he knows the answer to everything. This is simultaneously helpful and very irritating.