B-4：bank on/upon 依赖
A：Are you sure of your success in this election?
A: 你对这次选举的成功有把握吗？
B: No. I can't bank on their support.
B：没有。我不能指望他们的支援。
A: Why?
A: 为什么？
B: Because they're used to sitting on the fence.
B：因为他们是墙头草。
