明日、カラオケ行かない？ ごめん、明日はパーティーに行かないといけないの。＝ You wanna go for a karaoke tomorow? Let me see,oh sorry I have a party to go to, but next week end I should be ok.で可？
「明日、カラオケ行かない？」
"You wanna go karaoke tomorrow?" など。
この場合 for a は必要ないです。
「ごめん、明日行くパーティーがあるの、けど次の週末なら大丈夫なはず。」
"Sorry, I have a party to go to tomorrow but I should be *free next weekend." など
*OK でも大丈夫ですが空いてることをより表せます。
Weekend は単語一つです。
因みに let me see はスケジュールを確認中で待っててという意味で使ってると
思いますが普通に hold on などがよく使われます。
I'm sorry I already had plans to go to a party tomorrow. But I can go next time.
Oh I'm sorry, I will have to go next time because I already have plans for tomorrow.
I can go next time, but not tomorrow. I have to go to a party.
I'm sorry I already had plans to go to a party tomorrow. But I can go next time.
Oh I'm sorry, I will have to go next time because I already have plans for tomorrow.
I can go next time, but not tomorrow. I have to go to a party.
I'm supposed to attend a party tomorrow but I can go with you next time.
No, I can't go with you tomorrow because I have to attend a party.
I already made plans for tomorrow but I can go with you next time.
I'm sorry I already had plans to go to a party tomorrow. But I can go next time.（ごめんなさい、明日はパーティーに行くことになっているから。でも次は行けるよ）
Oh I'm sorry, I will have to go next time because I already have plans for tomorrow.（ごめんなさい、明日は予定があるのでこの次にしないといけません）
I can go next time, but not tomorrow. I have to go to a party.（次は行けるけど明日はダメです。パーティーに行かないといけないから）
I'm supposed to attend a party tomorrow but I can go with you next time.（明日はパーティーに出席することになっているから。でも次は行けるよ）
No, I can't go with you tomorrow because I have to attend a party.（明日は行けません、パーティーに出席することになっているから）
I already made plans for tomorrow but I can go with you next time.（明日はもう予定があるから。でも次は行けるよ）
I wish you had asked me sooner...
I am sorry but I have a previous engagement! "engagement" - made different plans
Sorry, but I was invited to a party tomorrow!
I would love to go but I am going to a party tomorrow!
I wish you had asked me sooner...（もう少し早く誘ってくれればよかったけど）
I am sorry but I have a previous engagement!（ごめんなさい、先約があるんです）
"engagement" - 他の予定
Sorry, but I was invited to a party tomorrow!（ごめんなさい、明日はパーティーに招待されていて）
I would love to go but I am going to a party tomorrow!（行きたいですけど、明日はパーティーに行くんです）
"Sorry I'm unavailable tomorrow"
Being 'Unavailable' is a expression used describe something you cannot use or obtain.
"Tomorrow I have a party, Maybe next time"
'Maybe next time' is a term used to be nice as you are sorry you cannot make plans they have made, that next time you are free to go.
"Sorry I'm unavailable tomorrow"（ごめんなさい、明日は予定があるんだ）
'Unavailable' は使ったり手に入れることのできないものを表します。
"Tomorrow I have a party, Maybe next time"（明日はパーティーがあるんだ、また次の機会にでも）
'Maybe next time' は、相手の誘いを感じよく断るための表現です。「次は行けます」という意味です。
Thank you for inviting me, but I will need to pass this time due to existing plans.
May I get a rain-check for another time because I already have plans to go to a party?
1.
By thanking the person for the invitation, one is expressing that they are glad to have been invited and would have likely attended. To "pass" on something is another way to say that one is declining the offer or invitation.
2.
A polite way to ask to be considered again for something is by asking, "May I get a rain-check?" It is a creative way of saying not this time but maybe another time.
1.
"Thank you for inviting me"（誘ってくれてありがとう）と伝えて、「誘ってくれてうれしい」「できれば参加したかった」と伝えています。"pass" は誘いや申し出を断るときの言い方です。
2.
"May I get a rain-check?" は「また今度誘ってください」の丁寧な言い方です。「今回は駄目だけどまた今度」のクリエイティブな言い方です。
I'm sorry, i won't be able to join you as i have a party tomorrow
Sorry, but i've already said i would go to this party tomorrow.
I'm sorry but i already have plans tomorrow night.
When trying to tell someone that you already have plans the next day, you could say something like "I'm very sorry however i already have plans tomorrow night." or "Sorry, but i have a party to attend tomorrow night.". Both of these are polite ways to tell someone that you are busy.
「明日はもう予定が入ってしまっている」と伝えたいなら、次のように言えます。
"I'm very sorry however I already have plans tomorrow night."（ごめんなさい、明日の夜はもう予定があるんです）
"Sorry, but I have a party to attend tomorrow night."（ごめんなさい、明日の夜はパーティーに行かないといけないんです）
どちらも「予定が入っている」の丁寧な言い方です。
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