"The proportions of state-owned companies and private owned companies are 17% and 20% respectively" Which one is correct? Or both? 1)"The proportions of state-owned companies and private owned companies are 17% and 20% respectively" 2)"The proportion of state-owned companies and private owned companies are 17% and 20% respectively" [In case anyone needs the context: The proportion means: how many percentages a certain type of companies account for in this data, e.g 17 state-owned companies' records in the 100 entire records, then the proportion is 17%.] The difference is the plural and singular form of "proportion". Is 2) incorrect? Also, I wondered whether there is any case where I could possibly keep the noun as singular form and still use the plural "are", in the structure: The [noun.] of A and B are C and D. Thank you!