根据所给词，将下列词分类，并在每一行的最后一格内再填一个相关词。

practice, sentence, cassette, comma, write, TV, video, frustrated,

grammar, speak, CD, learn, excited, pronunciation, ashamed, embarrassed

1. TV                                                              

2. speak                                                                 

3. sentence                                                                 

4. frustrated                                                                  

期前收缩