单项选择题

The suggested causes of a given phenomenon cannot always be independently observed, and so it is hard to ______ the possibility of there being explanations alternative to the one proposed.

A．account for
B．rule out
C．guard against
D．do with
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My Idea of professional Ethics for a Scientist
单项选择题
Yesterday you were acclaimed; today you are ______.Isn't life full of ups and downs
A．lauded
B．censured
C．savored
D．appraised
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