请问这里的as是什么用法？

fannybeibei

以下都为GWD：
In the 1820’s, anthracite coalfields opened in eastern Pennsylvania, and as canals and eventually railroads reached into the region, substantial supplies of coal were exported to the nation’s growing mills, forges, factories, and railways.

as后面接句子，前面有and

Birds known as honeyguides exhibit a unique pattern of behavior:the bird leads another animal, such as a honey-badger or a human, to a bees’ nest by chattering as it flies ahead; after the larger animal takes honey, the bird eats the wax and bee larvae.


as后面接句子，前面无and。。。



而且这两个as算什么用法呢？请指教！

fly12404

In the 1820’s, anthracite coalfields opened in eastern Pennsylvania, and as canals and eventually railroads reached into the region, substantial supplies of coal were exported to the nation’s growing mills, forges, factories, and railways.
這邊的ａｓ是當...的意思
and主要連ˊ接兩句子
anthracite coalfields opened... ,and substantial supplies of coal.....

Birds known as honeyguides exhibit a unique pattern of behavior:the bird leads another animal, such as a honey-badger or a human, to a bees’ nest by chattering as it flies ahead; after the larger animal takes honey, the bird eats the wax and bee larvae.
此處的ａｓ也是當
當他往上飛所發出的聲音　來引導其他動物
：）個人觀點　有可能有誤　歡迎討論

fannybeibei

thanks，fly～～