The singular form of "aspirin" is "aspirin." It's one of those words where the singular and plural are the same!
The singular form of the demonstrative pronoun 'these' is this.
Aspirin is acetylsalicylic acid. Consequently, it can act as a Lewis acid. Ammonia is a Lewis base. Therefore, ammonia and aspirin can react to form the ammonium salt of aspirin.
The singular form of "that" is "it."
The singular form is cuff.
it is already in its singular form.
"Stratum" is the singular form of stratum. The plural form is "strata".
The form hypothesis is the singular form. The plural form is hypotheses.
A singular form of dice is a die
The singular form of feet is foot.
The singular form of Oases is, Oasis.
"Wash" is the singular form of "wash."
The singular form of chromosomes is a chromatid.