There is a trick in answering multiple choices questions, esp. those written by professionals, such as SAT and similar American exams.

If you are given four choices, a), b), c), and d), you can be sure that two of them are outright WRONG. That leaves two for you to consider. However, one of those is actually wrong, leaving you with one final choice as your answer.

Here's an example:

> How many _________ did your mother buy this morning?
> A) fish B) meat C) tomatos D) glass

We can eliminate C) and D) because they don't match "many". Tomatoes is the correct plural form of tomato, and plural of glass is glasses.

That leaves A) and B). If you try the expression "how many meat" and "how many fish", you'll realize that "meat" is used with "much", not "many", leaving A) as the correct answer.

If you have five answers to choose from, A), B), C), D) and E), then the process is similar. At least two are completely wrong. One may appear correct, but is actually wrong upon re-examination. Then you must choose between the final two.

Here's a question that popped up on tw.bbs

> 以下這句為何不能選 B, C, 或D呢?

> How many _________ did your mother buy this morning?
> A) fish B) meat C) tomatos D) glass

> 答案是A, why?

meat -> much, not many
tomatoes, not tomatos
glasses, not glass

fish is correct because the plural of fish is still fish.