单项选择题
A.wooden blocks or dunnage placed between a deck load and the deck
B.the chains and shackles used to secure a deck cargo
C.a crate in which a deck cargo is packaged
D.cardboard separation pieces placed between deck loads to prevent chafing
单项选择题 At least（）radar transponder shall be carried on each side of every cargo ship of 500 gross tonnage and upwards.
单项选择题 As you hold a piece of manila line vertically in front of you，the strands run from the lower left to the upper right.Which type of line is this（）.
单项选择题 An intermediate spring is（）.