A．L1的灯丝全烧断
B．L2的灯丝全烧断
C．L1和L2的灯丝都全烧坏
D．电池会烧坏
答案：D
简述迁移的种类。
Starting motors，generators，and other spark producing devices should be mounted as high above the bilges as possible to（）.
A.keep them dry when the bilges are full of water
B.keep them cool when the vessel is underway
C.make them more accessible for repairs
D.prevent accidental ignition of any gasoline vapors that may have accumulated in the bilges
