单项选择题 Before sailing for a foreign port，what document must you get（）.

单项选择题 At any rate （）is liable for delay in obtaining the necessary Customs House papers for discharging，when the delay arises from the fact that special papers are required for the particular cargo carried.

单项选择题 According to the customs of this port，the work of opening and closing hatch covers is done by （）.