The [au] diphthong. The first sound of this diphthong is once again
a sound that does not stand on its own as a vowel sound in American English.
However ， it is very similar in sound to the aa as in bat. The way it
is different from that sound is that the jaw on aa， aa ， is tighter.
And on aa as in ow， it drops more. In that way ， it is similar to the
ah as in father. Also ， as you can see ， aa ， there's the lift here，
and it's not quite as extreme in the 'ow' ， 'ow'. In that sense， the
lips are also like the ah as in father. The tongue however， aa ， ow ，
is similar to the aa as in bat in that it's raised in the back and then
comes forward ， and that's what you see.

    The second sound is written as the uh as in pull. I do find ， however，
that it tends to taper a little bit towards the oo as in boo without the
lips actually coming into that position.

    [au]是一个双元音，它的第一个音并不像它本身所写的那样念作[a] ，但是
却和bat 中的[ ？] 音很相近。它俩的区别在于：发[ ？] 音时下颌收得紧些，
嘴角有明显的上扬；而发[au]中的第一个音时是下颌要下垂一点，嘴角没有那么
上扬。不过发两个音时，舌跟都要抬起然后向前舒展。[au]的第二个音写做pull
中的[u] ，但是它更接近于boo 中的[u：] 音，但是唇形没有收得那么紧。

    Sample words：

    cow 奶牛

    bough 大树枝

    sound 声音

    Sample sentence ：

    I came back from vacation and found my flowers dead and brown.度假
回来发现我养的花已经死了，都变成棕色的了。