They must have been enjoying themselves there, or they _____ so long. [ ]

A. wouldn't stay

B. wouldn't have stayed

C. needn't have stayed

D. couldn't stay

蓑衣花刀的切法是先在原料的一面象麦穗花刀那样剞一启蒙，再把原料翻过来，用直刀法与正面的斜刀纹成直角剞上一条条平等的刀纹，然后将原料切成一寸见（），提起来见两面透孔，呈蓑衣状

A、方块

B、正方

C、菱形

D、长方