Harrison complained that his colleagues ganged up on him. [VERB PREP. + on]

哈里森抱怨说他的同事联手对付他。

All the other parties ganged up to keep them out of power. [VERB PREP. to-infinitive]

其他政党全部联合起来使他们无法掌权。

All the girls in my class seemed to gang up against me. [V P + against]

我们班的女生好像都联合起来对付我。