th---有清与浊 两种读音： (1) th位于词首时，可以从词性上判别其应有的读音在名词、动词、形容词和数词中th发清辅音如：thing, theatre, thunder, thermos, Thursday, theory, theme, throat, thread, think, thank, thrive, thicken, thirteen, thirty, third, thousand, thick, thirsty, thoughtful, thorough 在代词和一些功能词中th发浊辅音.如： them, their, theirs, there, the, than, then, though, thus, therefore, they只有介词through是个例外 (2) th位于词尾（或音节之尾）时，其读音多数是清辅音，如：bath, breath, tooth, 等只有在少数单词中，如：with, smooth 中读浊音 (3) th在词中并且后面接er时，或者最后一个字母是不发音的e时，通常也发浊辅音例如：feather, weather, whether, leather, further, father, bathe, breathe, southern, northern, either等。
在其他情况下发清辅音例如：author, faithful, method, nothing, anything, healthy, wealthy 试读下列单词: mother, father, another, brother, health, wealth oo复合词读短[u]，还有d,k之前读短[u]，其余全部读长[u:]，特殊foot不读长，特殊food不读短，还有l,d间要读[]oo读长还是短,记住口诀就简单 d, k之前读短[u],food一词是特例;(如:good(好),book(书),look(看),特例词:food[u:](食物);) t前读长[u:],foot需要特殊记;(如:boot(靴子),tooth(牙齿),特例词:foot[u](脚);) 复合词中要读短,其余多数读长[u:]; l, s, d间读作[],例外还要特殊记如:blood(血),flood(洪水)等.)网上找的口诀二： 好、脚、k前不发长［u］， 房间、正午、食物、凉发长［u:］， 复合词-room中都读短［u］， 选择、扫帚、学校中读长［u:］， wood、动词过去式也读短［u］， 不久、月亮、也（太）必读长［u:］。
注：1．good foot football look cook book中要发［u］ 2．room noon afternoon food cool中发［u:］ 3．bedroom classroom reading-room sitting-room meeting-room dining-room中发［u］ 4．choose broom school中发［u:］ 5．wood took stood understood中发［u］ 6．soon moon too中发［u:］ 字母组合ee的发音[i:] beef deep free green meet sleep three tree ...字母组合ir的发音[ə:] bird first girl shirt thirty skirt ...i...e [ai]（元音字母i加辅音字母加不发音的元音字母e ）[ai] bike fine nine time shine kite five life ... 。