44 All workplaces must have smoke ________that sound a warning to people when they sense the
presence of smoke.
(A) containers
(B) filters
(C) detectors
(D) mentors
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統計: A(11), B(11), C(141), D(15), E(0) #2782540
統計: A(11), B(11), C(141), D(15), E(0) #2782540