The builders stop work at sunset.

施工人员在日落时停止了工作。

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The Commerce Department said Wednesday that builders started work at a seasonally adjusted annual rate of 890, 000 homes last month.

NPR: US Housing Starts Dip But Remain At Solid Pace

It will also be tricky to find builders who can work well at such altitudes (few people can do hard manual labour where the air is so thin).

ECONOMIST: Beneath the Southern Cross I stand