1.head to 引至，通到

例句:I let the horse drop his head to crop the spring grass.
我让马低下头啃吃春天的青草。

2.break up 分手；打碎；分裂

例句:Rubber bullets were used to break up the demonstration.
橡皮子弹被用来驱散示威人群。

3.prone to 易于；倾向于

例句:As they shorten, cells become more prone to disease and death.
细胞变小后就会更容易感染疾病，也更容易死亡。

4.set up 建立；设立；创立

例句:The city police set up roadblocks to check passing vehicles.
该市警察设置了路障以检查过往车辆。