她的行为对于她所代表的事业来说,可以被证明是危险的.
这个句子里的"cause"的意思不是特别常见的一个意项, "cause" in this sentence means:
an organization, plan, or activity that you are willing to support because it provides help or benefit to people who need it.
speak for someone/something means:
to represent the feelings or opinions of another person or group of people
其实这个句子不难, 认真查下字典就可以了. 考察的是常见词/词组的一些不常见的意思.