cautious of letting vague pronouncements cloud their reputations 是形容词短语修饰managers,此时不需要加be动词。这个句子换种写法是:a turbulent business environment also has senior managers who are cautious of letting vague pronouncements cloud their reputations.这个句子与原句是一个意思，用了从句，注意是are cautious of...
a turbulent business environment 是主语，has是谓语，senior managers 是宾语，cautious of letting vague pronouncements cloud their reputations.是一个定语从句，定语从句可以省略be。...
