Form the sentences. 连词成句。

1. small,  Danny's,  too,  is,  hat 

                                                       .

2. where,  live,  a ,  does,  bird   

                                                       ?                                   

3. have,  an,  elephant ,  a,  does,  trunk  

                                                       ?

4. ride,  can,  a,  rabbit 

                                                       ?                                    

5. there,  many,  are,  how,  books

                                                       ?

逆行法与顺行法用于检查______传导速度。