想問下一d簡單英文有無error

When there is a fire, do not use the lift
這個我認同, 或許用 If 會較適合
In conditional sentences when is used to describe a situation which is always true or a situation which you are sure will happen in the future.
eg: I always get migraines when it's this hot.
eg: When I finish school, I'm going to go to college.
If is used to describe a possible situation.
ege: It would be better for the environment if everyone went by bicycle.
或者 Fire Department 想利用火警是會發生的假設來警剔市民提高警覺吧
圖片參考：http://hk.yimg.com/i/icon/16/33.gif


垃圾房有很多不同的稱呼, 那一個也問題不大
Refuse room, refuse chamber, hopper room, garbage room, garbage chamber, trash room
還有Trash chute 垃圾槽
http://www.csb.gov.hk/hkgcsb/ol/netglos/housing/v2_g.htm
http://www.ust.hk/oudpa/terminology/signage.html

防火門應常關 Fire doors to be kept closed 文法是沒問題
其他建議:
Fire doors should be kept closed
Fire doors should always kept closed

小心升降機門 Keep clear of the lift doors
Use of water from fire services for purposes other than fire fighting is strictly prohibited
這2句我倒是覺得不錯
尤其消防用水嚴禁作其他用途那句, 清晰易明
Use of water from fire services for purposes other than fire fighting is strictly prohibited

＞＞When there is a fire, do not use the lift

這是第二次見人問這句，其實這句一點無錯，當有火警時，不要用電梯，只有火警的情形下。這是常識，用 WHEN 當然無問題。

你首先要決定你的句子是在甚麼情況下使用。若果是用來作標貼，那麼句子該用imperative（命令）型。不然的說，句子就該是indicative（指事）型。

Imperative:
When there is a fire, do not use the lift
Keep clear of the lift doors
Keep the fire doors closed

Indicative:
When there is a fire, you should not use the lift.
You should keep clear of the lift doors.
You should keep the fire doors closed.

以下的一句只可以用指示句去表達：
The use of water is restricted to the Fire Services

其實呢d句子係省略左少少野姐...

好似第一句咁...

when there is a fire, do not use the lift
當發生火警的時候, 不要使用升降機
-->文法無問題...不過唔係咁通順...
你可以咁改: When there is a fire, we should not use the lift
當發生火警的時候, 我們不應使用升降機

你所講...
呢到用when係唔岩,,,因為when有肯定/將會發生的意思,英文唔會咁用
其實你咁講就錯...
when唔係解有肯定/將會發生的意思...而是解作'當...的時候'
e.g. 1. When I was young, I played happily with my friends.
當我細個果陣時,,,我同我d朋友玩的好開心
2. I was really surprised when I bumped into my old friend yesterday.
當我昨日無意中遇到我的舊朋友時,,,我真的很意外

除左咁用之外,,,仲有一個用法
When可用作疑問副詞用...解作什麼時候,何時
e.g. 1. When will you have your dinner tonight?
你今晚會在什麼時候食晚飯?
2. When does the park open?
這個公園在何時開門?

另外...你響下方所舉出的句子文法正確...無問題bor...

全對......