"I couldn't catch a single fish today." は、文字通りに訳すと
「私は今日、一匹の魚も釣ることができなかった」という意味です。
1番目は直訳です。とは言え、自然な文章で問題無く通じます。
I couldn't (私は○○が出来なかった)
catch (捕まえる、魚を釣り上げる)
a single fish (魚一匹すらも)
today (今日)
もう一つの選択肢として、
"The fish weren't biting today."
(今日の魚は餌を噛んでくれなかった。)
と言う表現があります。
自分が失敗したより、『魚が機嫌じゃなかった。しょうがないね！』というニュアンスがあります。
I went fishing today but my catch wasn't good. I caught nothing.
I went fishing today but I didn't catch much.
I went fishing today but my catch wasn't good.- a 'catch' is a term we use to describe the amount of fish we get when we go fishing. Other examples, " I had a great catch today' (I caught a lot of fish). ' I caught nothing.' means you caught/got absolutely no fish or zero fish. Nothing is the opposite to something.
I went fishing today but I didn't catch much.- we can also use the word 'catch' as a verb. To catch something is to obtain, get, capture. In this context 'I didn't catch much.' means I didn't get a lot of fish
I went fishing today but my catch wasn't good.
今日魚釣りに行きましたが、あまり釣れませんでした）
'catch'とは、魚釣りに行った時の収獲を表現します。
他の例
" I had a great catch today'
（今日は大漁でした）
' I caught nothing.'とは、何も捕れなかったという意味です。
"nothing"の対義語は "something"です。
I went fishing today but I didn't catch much.
（今日魚釣りに行きましたが、全くつれませんでした）
また 'catch'を動詞として使うことが出来ます。 "To catch"とは捕まえるという意味です。
この 'I didn't catch much.'は、たくさん魚を捕まえることが出来なかった、と言う意味になります。
My productivity was not commensurate to the time spent!
To have nothing to show = If you have something/nothing to show for your work or effort, you have/have not won any advantage from it:
"I worked for two weeks, and $50 was all I had to show for it."
"I've been trying to write this essay all day and I have nothing to show for it."
Commensurate = corresponding in size or degree; in proportion, equivalent, equal, corresponding, correspondent, comparable, proportionate, proportional.
"Salary will be commensurate with age and experience."
To have nothing to show = 仕事や努力などから得た物が何もない、見せる物がない
"I worked for two weeks, and $50 was all I had to show for it."
（2週間働いて、50ドルだけがその結果です）
"I've been trying to write this essay all day and I have nothing to show for it."
（エッセイを書くために1日費やしていますが、何も見せられるようなものはありません）
Commensurate = サイズや程度の度合いが等しい
"Salary will be commensurate with age and experience."
(給料は年齢と経験に比例します）
Luck was not my side today. I didn't catch a single fish.
I went fishing today and caught nothing.
*Luck was not my side today. I didn't catch a single fish.- This means that you feel that you were unlucky today since you didn't catch any fish.
I didn't catch a single finish means you couldn't catch even one fish.
*I went fishing today and caught nothing.- Since this has happened in the past we use the past tense. So instead of catch we say caught.
Also remember that the plural of fish remains fish. We do not say fishes.
*Luck was not my side today. I didn't catch a single fish.
（今日はついてませんでした。一匹もつれませんでした）
これは、今日は運がよくなかったので魚が全然つれなかった、と言う意味です。
"I didn't catch a single finish"とは魚が一匹も釣れなかった、と言う意味です。
*I went fishing today and caught nothing.
（今日、魚釣りに行ったけど何も釣ることが出来ませんでした）
これは過去に起こった事なので、過去形を使います。
ですので、"catch"の代わりに"caught"と言います。
また、"fish"の複数形は"fish"のままだと言う事を忘れないようにしましょう。
"fishes"とは言いません。
I wanted to catch some fish, but I was not successful.
The first phrase "I didn't catch any fish" uses an abbreviated negative verb. Didn't = Did Not. It tells who you are speaking to that you weren't able to catch any fish.
"I wanted to catch some fish" tells the person your speaking to of your desire to catch a fish, then the final clause "but I was not successful" indicates that you were not able to.
I hope this helps
1つ目のフレーズ "I didn't catch any fish." は、否定形の省略 didn't (=did not)をつかっています。
あなたが魚を全く釣れなかったことを意味します。
"I wanted to catch some fish"
こちらは魚を釣りたかったという気持ちを伝えつつ、
"but I was not successful."
と続けることで、上手く行かなかったことが伝わります。
参考になれば幸いです。
While fishing today, I didn't catch a single fish.
I came back empty handed from fishing today.
To express that you didn't get any fish while fishing you can say, "When I went fishing, I didn't catch a thing." When you say you came back from from fishing "empty-handed" which means that you didn't catch any fish.
魚釣りに行って一匹も釣れなかったときは、
"When I went fishing, I didn't catch a thing."
釣りに行ったとき、何も釣れなかった。
ということができます。
釣りから帰ってきて、 "empty-handed"と言うと、一匹も釣れなかったという意味になります。
"I didn't catch any fish today" will be used in the same day, for instance if you went fishing in the morning and told a friend about your fishing trip later in the day. You can also say that when you went fishing you were not able to catch a fish. Then, when "a single fish" it really means you caught zero fish, where as sometimes the others can be more metaphorical.
"I didn't catch any fish today"はあなたが朝釣りに行って、その後、同じ日に友達に釣りについて話す場合など、同日中に使われる表現です。
釣りに行って、魚が釣れなかった時に使える表現としてまた、"a single fish"がありますが、それは本当に一匹もつれない"zero fish"のことを指し、時々比喩的に使われることもあります。
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