Please close the door behind you as flies could come in.
Keep the door closed in case insects could fly in.
Keep the window closed in case insects could fly in.
This is a sign that is usually put up on the doors or windows of offices in hot weather when flies are more active. You don't see it that often in cold weather. When a person reads this sign they will understand to close the door or window to stop any flies or insects from coming inside.
The food here is too good to share! Please keep the doors closed!
Please keep the flies out by keeping this door closed!
Please keep the door closed at all times. - This implies that you want the door kept closed. This means that once someone enters or leaves, you would like them to close the door. You could also say: Please close the door behind you.
If you are in a restaurant and want to tell your customers in a joking way to keep the flies out you could say:
Flies are attracted to our wonderful food! Please close the door if you don't want to share! or
The food here is too good to share! Please keep the doors closed! (This would work well with a picture of a fly on it the poster!)
Please keep the door closed at all times.
常にドアを閉めておいてください。
これは、あなたがドアを閉めておきたいことを指します。これは、いったん誰かが入ったり、出たりすると、ドアを閉めて欲しいという意味です。また、以下のようにも言うことができます。
Please close the door behind you.
出たら（入ったら）ドアを閉めてください。
レストランにいるときは、お客さんにハエを入れたくないので冗談ぽく以下のように言うことができます。
Flies are attracted to our wonderful food! Please close the door if you don't want to share!
ハエが私たちのおいしい料理に引き付けられますので、（料理を）シェアしたくない方はドアを閉めてください。
The food here is too good to share! Please keep the doors closed! (This would work well with a picture of a fly on it the poster!)
ここの料理は、おいしすぎてシェアできません！ドアを閉めてください！（これは、ハエの写真のポスターがあるといいでしょう）
Please keep the door closed so that flies don't enter.
It's always a good idea to use please when making a request. "So that" describes a cause and effect situation which will make it clear to the reader why the door needs to be closed. I hope that this helps. :)
When you want to put on a sign that warns people to close the door because flies usually come in that way; then you may say this in the following ways:
-Please keep the door closed as flies will come in
-Keep the door closed to keep the flies out
「ハエが入ってくるので扉を閉めてください」という貼り紙を貼りたいなら、次のように言えます。
-Please keep the door closed as flies will come in（ハエが入ってくるので扉は閉めておいてください）
-Keep the door closed to keep the flies out（ハエが入らないように扉を閉めておいてください）
To not let flies in, please remember to shut the door behind you.
A common phrase to tell people to close the door is "shut the door behind you" which means after they step into the room or store, they will close the door that would be now behind them. A good way to sound polite is to add "please"and "remember", it also makes it sound a little more formal.
"shut the door behind you" は、ドアを閉めるよう伝える一般的なフレーズです。これは、部屋または店に入ったら、「自分の後ろにあるドアを閉めてください」という意味です。
"please" や "remember" を加えると丁寧で、また少しフォーマルな響きになります。
Please keep the door closed to stop the flies coming in
When letting people know a mesaage then it is often best to keep it simple to get the message across so you could simply say 'please keep the door closed at all times' you could also say 'please keep the door closed as flies will come in' this explains why you want the door shut
人にメッセージを伝えるときは、シンプルがいいです。ですから、'please keep the door closed at all times'（扉は必ず閉めてください）と言えます。
また、'please keep the door closed as flies will come in'（ハエが入るので扉は閉めておいてください）と言うこともできます。これは、なぜ扉を閉めてほしいのか伝えています。
With notices, the usual rules of grammar and organisation are often discarded in order to convey the message in a succinct and forceful way. Articles, connectors and polite niceties all fall by the wayside.
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アイルランド 
アメリカ合衆国 
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