Should we write “allow” or ”allows” in “require that the class allow[s]”? [duplicate]

Solution 1:

This is an example of the subjunctive:

The Subjunctive is used to emphasize urgency or importance. It is used after certain expressions (see below).

Examples:

I suggest that he study.
Is it essential that we be there?
Don recommended that you join the committee.

http://www.englishpage.com/minitutorials/subjunctive.html

Solution 2:

No, it's fine without s. Requires that takes the subjunctive.

Solution 3:

That is the case of Present Subjunctive in the sentences denoting requirement, advice, demand, order, etc. When the main clause has the verb denoting one of the above mentioned meanings, then in subordinate clauses subjunctive is used, i.e. a verb without -s.