The fire broke out in Odessa's trade union's building where the pro-Russian protesters head headquarters.

开枪事件发生在敖德萨的商会大楼，这里也是亲俄罗斯抗议者的总部。

And Uber has agreed to recognize a trade union for the first time in a landmark deal that should benefit gig economy workers.

优步(Uber)首次同意承认一个工会，这是一项里程碑式的协议，应该对零工经济劳动者有利。

Gideon Tanda is a leader of one of the teacher's trade unions that called the strike.

吉迪恩·坦达 (Gideon Tanda) 是发起罢工的教师工会之一的领导人。

The second sentence mentions 'benefits', which appears in heading number two, but this sentence says that people don't know the benefits of joining a trade union, which is a different context from heading number two.

第二个句子提到了“益处”，这在第二个标题中出现了，但是这个句子说人们并不知道加入工会的好处，这和第二个标题语境完全不同。