Affer mihi aquam ad manūs!
I’m struggling with this one.
Bring me water “for my hands”. ?
Not at all sure what else ad manūs could mean.
Ad here could be translated as for. It’s quite a normal expression. See this from Petronius:
“aquam poposcit ad manus PETR.27.6”
Clearly literally the idea is “bring to my hands” but that is not an English expression. Dont forget that Latin expressions are not the same as English expressions. How you translate something and the literal meaning are not one of the same thing.
I thought the whole purpose of lingua Latina is that you immerse yourself in Latin idiom and you dont need to translate.
Thanks, Seneca. I wasn’t aware that ad, in some contexts, could also be translated as for.
Prepositions always have a wider range of usage than the few glosses listed for them in beginning textbooks. You only pick this up through reading enough Latin to see those various uses.
Seneca, I’m currently using Ørberg (curriculum switch starting last year). While it drastically reduces the amount of English (or any other primary language) the student needs, many teachers still use translation as part of instruction.
When you read Caesar you will see that “ad plus a gerundive” is a common construction as in “Ad eās rēs conficiendās…” - for those things going to be accomplished. Dont worry about it too much now but be alive to the variety of meanings ad can take in various contexts. The entry for ad in the Oxford latin Dictionary runs to over two pages!
Barry I have just seen your post, thanks for sharing your experience.
My too compressed point was that understanding what the Latin means (as Pianophile did) is different from translating it. When teaching I guess translation is an inevitable part of testing understanding.
Thanks for alerting me to that, Barry; so far first prize must go the Ablative. 
Edit: Seneca, just seen your post - again many thanks.