We were unable to get funding and therefore had to abandon the project.

therefore 是副词，由 there（那里）和 fore（前面）组成，字面意思是"从那里往前"，引申为"因此、所以"。在句中表示前因后果的逻辑关系，连接"无法获得资金"和"放弃项目"这两个事实。