Every step crumbled up Numbers of minute grey shells, empty and dry, that crunched under foot like hoar-frost or fragile beads.
每一步都要踩碎不少细小的灰色的贝壳，壳已风干，内中空无一物，在脚下咭嘎地响犹如白霜或易碎的珠子。
2
The paper integrates integer programming and grey model, then gives the grey integer programming model of searching submarine, provides test method and resolution step, finally illustrates it.
Turning down a quiet cul-da-sac, the three identical homes, all clad in shades of grey, step along the sloping lot, resonating with the surrounding greenery as well as the nearby bungalows.