We must not cut down too many trees.

我们不能砍伐太多树木。

同一单元的其他句子

• We should recycle paper and plastic.我们应该回收纸张和塑料。
• Don't throw trash on the ground.不要往地上扔垃圾。
• Can you sort the garbage at home?你在家里会分类垃圾吗？
• The recycling bin is next to the door.回收箱在门旁边。
• Please reuse old boxes for storage.请重复使用旧盒子来储物。