Stop在这里指管风琴的音栓，这个短语是什么意思呢？请看对话：

    A: I want to pick your brain. Which party do you think will win the election?

    B: Well, it’s hard to say at this stage. Both sides promise to pull out all the stops, running more TV and newspaper ads and making more phone calls to supporters.

    Note: This idiom means to “make every possible effort.” The popular belief is that this phrase derives from the manner of construction of pipe organs. These instruments have stops to control the air flow through the pipes and pulling them out increases the musical volume. The first person to have used the phrase in a figurative, that is, non-organ related, sense appears to have been Matthew Arnold, in “Essays in Criticism,” 1865.