Questions & Answers about Wij zijn klein, maar zij zijn groot.
Why does the sentence use wij and zij instead of the shorter forms we and ze?
Because of the contrast! In Dutch, you use the stronger, emphasized forms (wij and zij) when comparing or contrasting subjects. Since we are contrasting 'us' being small with 'them' being big, the strong forms are used instead of the unstressed we and ze.
Is it a coincidence that both parts of the sentence use the exact same verb form, zijn?
Not a coincidence at all. In Dutch, all plural subject pronouns (wij, jullie, and zij) share the exact same verb form. For the verb 'to be', that plural form is zijn.
Wait, I thought zij meant 'she'. How do we know it means 'they' here?
You are right that zij can mean both 'she' and 'they'. You can always tell the difference by looking at the verb! Because the verb here is the plural zijn (are), zij has to mean 'they'. If it meant 'she', the verb would be singular: zij is (she is).
Why don't the adjectives klein and groot get an extra -e at the end?
Adjectives usually only get an added -e when they are placed right in front of the noun they describe. When they come after the verb to describe the subject, like in this sentence, they always stay in their basic, dictionary form.