- 搜標(biāo)題
- 搜題干
- 搜選項(xiàng)
單項(xiàng)選擇題
A man aboard a vessel，signaling by raising and lowering his outstretched arms to each side，is indicating（）.
A.danger，stay away
B.all is clear，it is safe to pass
C.the vessel is anchored
D.a distress signal
