引导词可以引导一个句子或者是短语.
that where when等都是引导词.
至于说一个句子中出现两个谓语的话分多种情况：
1.有一个动词（其中一个位于吧）做非谓语动词,另外一个做谓语动词.如变成doing格式、to do格式等.
There was a long silence,broken only by his heavy breathing,and by the measured tapping of Sherlock Holmes' finger-tips upon the edge of the table.
句中broken等就是非谓语动词,而was为句子中真正的谓语动词.
I tried to look out of the windows to see something of where we were,but they were made of frosted glass.
tried是谓语动词,而to look out of,to see等不能叫句子中的谓语动词了.
2.引入引导词,将另一个谓语设定到引导词所引导的句子或者短语中,从而以另外一个谓语为主.
A woman appeared with a lamp in her hand,which she held above her head ,pushing her face forward and peering at us.
句中which所引导的句子中就有a woman的动作词,而它却不做谓语.
如果要问常用的连词的话那就多了
and or butnot only……but alsoas well as…………太多了.
至于关系代词和关系副词啊,有点难讲……
不负责任的一句话就是：具体情况具体分析.