The doubt that arises when the verb is “to lack” is very common. We don't know if we left it singular or plural!
Sometimes we say: It's ten days until the Cup. And sometimes we say: The Cup is ten days away.
Or: Two points are missing or Two points are missing.
But after all, when to put in the singular and when to put it in the plural?
Remember the following: The verb “to lack”, like most, will have a subject. Verbal agreement establishes that the verb must agree with its subject. And this case is NOT an exception to the rule.
Therefore, whenever you are in doubt, note who is the subject of the sentence and its inflection.
According to the explanation and taking as examples the prayers specified above, we will have:
a) There are ten days until the Cup and
b) Two points are missing.
You may be wondering why in the second sentence the verb was singular, since it is "a colon". But note the following. “Lack” does not refer to the colon, but to “observe”, that is, what is missing is to observe and not “colon”!
See other examples:
1. I wanted to go this week, but my vacation is a few days away.
2. After the elections were held, only two ballot boxes remain.
3. We go to the movies, all that's left is to buy tickets.
4. We have two hours to go.
5. Two days to the weekend.
By Sabrina Vilarinho
Graduated in Letters
Brazil School Team
Source: Brazil School - https://brasilescola.uol.com.br/gramatica/falta-ou-faltam.htm