Measure Word + 老鼠 / 一 + 只 + 老鼠
The noun 老鼠 (lǎoshǔ) means 'mouse' or 'rat,' referring to the common rodent. Despite containing 老 (old), the word simply means mouse — the 老 is a prefix with no age meaning. It is one of the most commonly known animal words in Chinese.
厨房里好像有老鼠,昨晚听到了响声。
Chúfáng lǐ hǎoxiàng yǒu lǎoshǔ, zuówǎn tīngdào le xiǎngshēng.
There seem to be mice in the kitchen; I heard noises last night.
猫是抓老鼠的高手。
Māo shì zhuā lǎoshǔ de gāoshǒu.
Cats are experts at catching mice.
她最怕老鼠,看到就会尖叫。
Tā zuì pà lǎoshǔ, kàndào jiù huì jiānjiào.
She's most afraid of mice; she screams whenever she sees one.