我有兩個弟弟

有 means “to have / there is”: 我有哥哥 (I have an older brother). To say the opposite, put 沒 in front: 我沒有哥哥 (I don’t have older brothers). 沒 is one of Mandarin’s two main negators — and 有 is ALWAYS negated with 沒, never 不.

Statement + 嗎 = yes/no question, no word-order change: 你有兄弟姊妹嗎？ (Do you have siblings?) · 妳有哥哥嗎？ (Do you have older brothers?)

Mandarin counts nouns through a measure word: Numeral + 個 + Noun — 一個姊姊 (one older sister), 兩個弟弟 (two younger brothers). And note: counting quantities uses 兩, not 二 — 兩個, never 二個.

Adverbs sit AFTER the subject and BEFORE the verb: S + 也 + V — 我也有一個姊姊 (I also have an older sister) · 他也是臺灣人 (he is also Taiwanese). Never at the end like English “too”.

Same adverb slot as 也: 我只有一個姊姊 (I only have one older sister) — Gloria’s line in the dialogue: no older brothers, no younger brothers, 只有 one older sister.