They seem to be wide lines drawn with some white material.

这看似是由白色材料绘制而成的宽线。

youdao

The white material at the top of the cliff, near the planet's North Pole, is carbon dioxide ice.

照片上显示的悬崖上的白色物质是位于火星北极地区的干冰。

youdao

Photographic evidence settles the debate over the nature of the white material seen in photographs sent back by the craft.

航天器传回的照片上有白色的物质，摄影证据终结了关于这种物质究竟是何种自然物的争论。

youdao

Candy stood above Marjorie and trained her flashlight onto the pearly white material.

NEWYORKER: The Visitor

Then she tries sandals made with white khaki material.

CNN: ASIANOW - TIME Asia

Using white Italian marble, a material associated with the Western idealisation of the perfect human form, the works are both celebratory and subversive.

BBC: NEWS | Programmes | Newsnight | Newsnight Review | Marc Quinn