We do that when the sound before is unvoiced.

当其前面的为不发时，我们会这样做。

And a 'th' at the end of a word is usually unvoiced.

单词末尾的“th”一般清辅。

So the 'th' at the start of content words is usually unvoiced.

所以实义词之前的“th”一般清辅。

It's unvoiced because there's no vibration here.

它无声的，因为这里没有振动。

If the first one is unvoiced, the second one will sou nd unvoiced, no matter what you do.

如果第一个辅清，无论怎样，第二个会清。

Now if there is a 'th' in the middle of a word, before a consonant, it's usually unvoiced.

如果在单词的中间、辅之前有一个“th”的话，通常清辅。

They have the same tongue and mouth position but one uses air to make the sound, it's unvoiced.

它们的舌头和嘴的位置一样的，但其中一个不发的。

The first one is voiced, the second one is unvoiced.

第一个浊，第二个清。

If you look it up in IPA, thank has unvoiced TH, AA as in Bat, NG sound, K.

如果你在 IPA 中查找它， thank 有清 TH，AA 在 Bat 中， NG 声， K。

Now we have an ed ending, the sound before is unvoiced so that ed ending is pronounced as a T.

现在我们有一个 ed 结尾，之前的声清的，所以 ed 结尾发为 T。

The " s" is unvoiced in the noun form, for those of you who are interested in that sort of thing.

对于那些对这类事情感兴趣的人来说， “s” 在名词形式中清的。

S and Z are a pair, they go together because they have the same mouth position, and S is unvoiced, and that's considered strong.

S 和 Z 一组辅，它们一组因为它们的发位置一样的，S 清，而且一个强。

The ED ending is a T when the sound before is unvoiced. The K is unvoiced, so the ED ending here is a T.

当前面的声清时，ED 结尾 T。 K 清，所以这里结尾的 ED T。

Now, if the last sound of the base form of the verb is unvoiced, then that means that there's no vibration or almost no vibration, alright, when you say it.

现在，如果动词基本形式的最后一个清，那就意味着没有振动或几乎没有振动， 好吧，当你说它的时候。

So, if the sound before the letter T and the word to is unvoiced like here, S is an unvoiced sound S, then the T will probably be a true T.

所以，如果字母 T 之前的声和的单词像这里一样清，S 清 S，那么 T 很可能真正的 T。