1. A grain of corn is on the table.
2. Two grains of corn are on the table.
(Are they OK? Please focus on the plural forms?)
3. The eighth square on the second row needed 256 spoons of rice, which amounted to a bowl.
(In this sentence 'which' refers to '256 spoons of rice, so 'which' can be changed into, 'and they' or 'and it'?)
1 and 2. Correct.
3. Are "256 spoons" singular or plural?
'spoons' = plural
Use the plural verb form.
1. Both sentences are grammatically correct. The first sentence "A grain of corn is on the table" is singular, indicating that there is only one grain of corn on the table. The word "grain" is singular, and so is its corresponding verb "is."
The second sentence "Two grains of corn are on the table" is plural, indicating that there are two grains of corn on the table. The word "grains" is plural, and its corresponding verb "are" agrees with that.
So, depending on the number of grains of corn, you can correctly use either the singular form or the plural form.
2. In the third sentence, "which" refers to "256 spoons of rice." The use of "which" is appropriate in this context, as it provides additional information about the quantity of rice required.
While "which" can be replaced with "and they" or "and it," the pronoun choice depends on the intended meaning. If using "and they," it would be interpreted as referring to the rice spoons as individual entities: "256 spoons of rice, and they amounted to a bowl." If using "and it," it would be interpreted as referring to the total quantity of rice as a collective unit: "256 spoons of rice, and it amounted to a bowl."
Consider the intended emphasis and meaning when choosing between "and they" or "and it" as alternatives to "which."