问题补充：
Emergency line operators must always calm and make sure that they get all the information they need to send help.
A. grow
B. stay
C. appear
D. become
答案：
A. grow
(答案→)B. stay
C. appear
D. become
解析：
这题考查连系动词的用法，stay calm“保持冷静”，grow、become强调变化，appear似乎，都不符合。选B。
