被动语态后如果要再加动词是不是要先加to

两句都不对.你想说的话应该这样说：
Bhutto was assassinated,which rocked Pakistan.布托被暗杀了,这件事震动了巴基斯坦.
被动语态后再加动词,可能用不定式,也可能用现在分词或过去分词.这要看主动语态时原文是什么形式的动词做宾语补足语.
如：The boss made me work all day long.
I was made to work all day long.
I saw him working in the fields.
He was seen working in the fields.
I saw his father beat him.
I saw him beaten by his father.
如果主动语态时,宾语补足语是省略了to的不定式,变成被动时要补回这个to.如第一二两句.如果主动语态时宾语补足语是现在分词,变成被动时还是现在分词.如3、4两句.如果主动语态时后面的宾语是不定式的逻辑主语,可以把第二个动词的宾语变成第一个动词的宾语并把第二个动词变成过去分词.如5、6两句.
再如：The emperor order the cheats weave the cloth.
The emperor ordered the cloth (to be) woven.