空心的

例句：

1. 1. The tree was hollow, and it could be seen through easily.
   这棵树是空心的，可以很容易地看到。
2. 2. The balloon was hollow, and the children were afraid to touch it.
   这个气球是空心的，孩子们不敢碰它。
3. 3.The house was hollow, and there was a feeling of emptiness inside.
   这座房子是空心的，里面有一种空虚的感觉。