Emergency line operators must always calm and make sure that they get all the in
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Emergency line operators must always ________ calm and make sure that they get all the information they need to send help.
A. grow B. appear C. become D. stay
试题答案
D
考查系动词的用法。根据句意“紧急热线接线员必须保持镇定”可知答案为D. stay“保持”。