Wow, I've learned one more thing about English. Thank you, Paco and CJ. What is missing, though, is an explanation about why the bare infinitive verb is used there. It's rather unusual, isn't it? Can anybody offer your expertise on this?
Paco, regarding your last question, let me try.
1. It is [essential/necessary/imperative/important/vital/desirable/best/...] that S V ...
2. [verbs or nouns with the concept of demand, whether forceful or weak] that S V...
= [order/command/demand/require/request/ask/recommend/advise/suggest/insist/declare/plead/
instruct/necessitate/prefer...] that S V ...
*If any of these verbs don't have the concept of demand, they do not choose a root form.'suggest'
and 'insist' are good examples.
3. [on condition/with the intent] that S V ... *Note: The root form of a verb is optional.
4. lest that S V ...
.........................................
A few example sentences are retrieved from my personal database.
[vital]
It is vital that a record of the past be kept so that people have a sense of their history.
[ask] She asked her name not be identified.
[necessitate]
The dog's declining health necessitated that he be administered medication daily.
[ensure]
Being a rebel was one way for Mel Gibson to ensure that he not get lost in
such a large brood.
I hope this is what you want, Paco.The list could be lengthened by others.
Have a great day!