单项选择题
A.by turning the globe clockwise B.by a switch at each light C.by a light sensor D.automatically when the raft is inflated
A.automatically as the liferaft inflates B.with a switch near the boarding handle C.at night because the light has a photosensitive switch D.by screwing the bulb in after the raft is inflated
A.replaced annually B.tested monthly C.serviced annually D.overhauled quarterly