1·Big trees face threats from elsewhere.
大树面临着来自其他地方的威胁。
2·Big trees are incredibly important ecologically.
大树对生态环境非常重要。
3·All the big trees, the green lawns, and the old buildings with tall columns.
所有大树，绿色草坪，以及有高大石柱的老建筑。
4·With no young trees to replace them, it is only a matter of time before most of the big trees disappear.
由于没有幼树来代替它们，大多数大树消失只是时间问题。
5·Aggressive wildfire control has left California forests crowded with small trees that compete with big trees for resources.
来势汹汹的野火控制使得加利福尼亚的森林拥挤不堪，小树与大树争夺资源。
6·The big trees were the symbol of the school.
这些大树是这所学校的象征。
7·He looked for big trees and old trees in Canada.
他在加拿大寻找大树和古树。
8·On Vancouver Island in Canada, there are so many big trees.
加拿大的温哥华岛上有许多参天大树。
9·There are many big trees.
这有许多大树。
10·The bushes have grown into big trees.
矮树丛长成了参天大树。