船舶抵港前已发生的或可能引起船舶或货物受到损害的，在（）时候将海事声明递交签证机关。

A position that is obtained by using two or more intersecting lines of position taken at nearly the same time，is a(n) （）.

A position that is obtained by using two or more intersecting lines of position，taken at nearly the same time，is a(n)（）.

海事行政强制措施应当由（）海事执法人员实施。

A line of position from a celestial observation is a segment of a （）.

A single line of position combined with a dead-reckoning position results in a(n)（）.

A single line of position combined with a dead-reckoning position results in a(n)（）.

A position obtained by crossing lines of position taken at different times and advanced to a common time is a(n)（）.

Which single access list statement will combine all four of these statements into a single statement that will have exactly the same effect（）。

海事的定义有广义和狭义之分，下列哪些属于狭义上的海事（）。

（）是海事履职的政治保障，（）是海事履职的根本要求，（）是海事履职的重要基础。

如果要在语句：a=Array(1，2，3，4，5)的前面声明变量a，则正确的声明是