When they are pronounced, no pause of phone before them, and no fixed accent in themselves.

发音时前面不能出现语音的停顿，而且本身没有固定的重音。

youdao

When they are pronounced, no pause of phone before them, and no fixed accent in themselves.

发音时前面不能出现语音的停顿，而且本身没有固定的重音。

youdao