輔音字符 th 有 清與濁 兩種讀音：
1 當(dāng)位于詞首時(shí),可以從詞性上判別其應(yīng)有的讀音.請(qǐng)看：
第一類(lèi)：在以下 4種 詞類(lèi) th 讀 清音,即國(guó)際音標(biāo)的 θ ：
a. Noun 名詞：thing, theatre, thumb大拇指, thunder雷,
thermos熱水瓶, Thursday, theory, theme, throat喉嚨, thread線
b. Verb 動(dòng)詞：think, thank, throw, thrive, thicken,
c.Numeral 數(shù)詞：three, thirteen, thirty, third, thousand
d.Adjective 形容詞：thin, thick, thirsty, thoughtful,
thorough徹底的
第二類(lèi)：在以下 兩種 詞類(lèi) th 讀 濁音：
a. Pronoun 代詞：they, them, their, theirs, this, these,
that, those, there, thy[舊時(shí)用法]你的
b. Functional terms 功能詞：the, than, then, though, thus,
therefore
2 當(dāng)位于詞尾（或音節(jié)之尾）時(shí),其讀音多數(shù)是清音,如：bath, breath, both, cloth, tooth, health, wealth, arithmetic 等.只有在少數(shù)單詞中,如：with, smooth 中讀濁音.
3 當(dāng)位于兩個(gè)元音之間時(shí),其讀音多數(shù)是濁音.如：other, mother, brother, another, father, weather, feather, leather, further, breathe.
但是,也有讀清音的.如在單詞 method, nothing, anything, sympathy, sympathetic, mathematics, healthy, wealthy, Luther, Marathon(馬拉松)等.