"Small bamboo rafts in the middle reaches of the river, walking on both sides of the towering green mountains." The first sentence in the poem is based on ______ as the reference system, and the seco

"Small bamboo rafts in the middle reaches of the river, walking on both sides of the towering green mountains." The first sentence in the poem is based on ______ as the reference system, and the second sentence is based on ______ as the reference system

The position of the bamboo rafts relative to the bank is constantly changing, so the "Midstream of the Bamboo Raft River" is based on the green hills (bank) as the reference;

The position of the green mountains on both sides of the bank relative to the bamboo rafts is constantly changing, then "Walking on both sides of Qingshan Mountain" uses bamboo rafts as a reference.

So the answer is: green mountains, bamboo rafts.