连词成句。

1. are   four   seasons   there   a   year   in    

                                                                                    .

2. to   ski   like   I   on   snow   the   

                                                                                    .

3. do   else   do   in   China   winter   what   you   in  

                                                                                    ? 

4. season   your   favourite   what   is   

                                                                                    ?

5. to   going   teach   is   Li Ming   Danny   to   skate

                                                                                    .

如图所示的电路图，当开关S₁接b，S₂断开时，两灯泡是______联；当开关S₁接a，S₂闭合时，两灯泡是______联．（选填“串”或“并”）