”How much is” OR ”How much are”

看這個問題，首先要弄清楚，你所問的主題(subject)是什麼。

這條問題要問的是總共的價錢(total cost)，不是你買一件或兩件東西。Total cost 是一個數字，所以應該用is。

How much is the lemon tea and the sushi?

其實這句句子，比較清楚的寫法是

How much is the total cost for the lemon tea and the sushi? 或
How much does it cost for the lemon tea and the sushi?

但由於太累贅，所以一般都簡寫 How much is the lemon tea and the sushi?不過，針無兩頭利，這樣寫在學習上就多了一重隱蔽。

至於答案，可以是It is twenty dollars and fifty cents ，這裡的it是指cost， 或 They cost twenty dollars and fifty cents都可以，但絶不能寫They are twenty dollars and fifty cents.

如果一定要用are，就是問每一件東西的價錢，而句子應改作

How much are the costs for each of the lemon tea and the sushi?

因為你在問兩個價錢(costs)。而答案當然就要改成

The costs are $x and $y (for the lemon tea and sushi) respectively.

如果兩件東西價錢相同，就可以說

They are both $x。

留意They是指costs，不是那兩件東西。