Translation Practice: Three English Sentences: Translation Practice Translation Practice: Three English Sentences

This is knit-picky, but I'd change the order so the topic, translation practice, comes first.

She hasn't done her homework yet because she has been practicing the piano since theall afternoon. She hasn't done her homework yet because she has been practicing the piano all afternoon.

"Since the afternoon" AI likes this phrase and approves your use of it. That said, if she practiced during the entire afternoon, I prefer "all afternoon." Another option I prefer is to change the wording: "she has spent the afternoon / the entire afternoon practicing the piano."

She hasn't done her homework yet because she has been practicing the piano since theall afternoon. She hasn't done her homework yet because she has been practicing the piano all afternoon.

Either 'all afternoon' or you can use 'since + time' such as 'since 3 o'clock'

She hasn't done her homework yet because she has been practicing the piano since theis afternoon. She hasn't done her homework yet because she has been practicing the piano since this afternoon.

"since the morning," "since the afternoon," etc. sound weird to me. I feel like I only hear this phrasing with "this" not "the"

She hasn't done her homework yet because she has been practicing the piano since theall afternoon. She hasn't done her homework yet because she has been practicing the piano all afternoon.

"Since the afternoon" sounds a little stiff, or overly proper. A more casual way to phrase something like this would be to say: "she was practicing all afternoon" or "he is tired this morning because he was up all night".

She hasn't done her homework yet because she has been practicing the piano since ththe whole afternoon. She hasn't done her homework yet because she has been practicing the piano the whole afternoon.

「午後から」と「午後ずっと」の違い

She hasn't done her homework yet because she has been practicing the piano since the afternoon. She hasn't done her homework yet because she has been practicing the piano since the afternoon.

or: "practicing playing the piano"

He couldn't get into his house because he had forgotten his key the key when he left. He couldn't get into his house because he forgot the key when he left.

The nuance of when and where he forgot the key was missing in the English version. The "when he left" part tells the reader that 1) The key was left in the house . 2) The key was forgotten at the time he left the house.

If it hadn't been for you, I wouldn't have finished that job. If it hadn't been for you, I wouldn't have finished that job.

Grammatically correct. Contrast with: "Thanks to you, I finished that job!"

If it hadn't been for you, I wouldn't have finished that job. If it hadn't been for you, I wouldn't have finished that job.

Good, but also "If it hadn't been for your help" or "If not for your help" (sounds a little old-fashioned)

If it hadn't been for you, I wprobably couldn't have finished that job. If it hadn't been for you, I probably couldn't have finished that job.

Changed from "wouldn't" to "couldn't" for the "unable to" nuance of 出来なかった Added "probably" for the uncertainty nuance of でしょう