As the mountains were covered with a _______ of cloud , we could

As the mountains were covered with a _______ of cloud , we couldn't see the tops.
A、sheet
B、coating
C、veil
D、shade
【正确答案】：C
【名师解析】:选项C "veil" 是正确的答案，因为它在句子中的含义是“面纱”或“幕布”，用来形容云层像一层薄纱覆盖在山上，使得山顶看不见。其他选项如 "sheet"（薄片）、"coating"（涂层）和 "shade"（阴影）虽然也可以与云层相关，但它们不能准确表达云层覆盖山的效果。