根据句意、汉语或首字母提示，补全单词，完成句子。

1. I can't imagine what the life of the animals will be like when they are living in the cages.

2. I sent them flowers as an_____(表达)of thanks.

3. Ten more houses will have been b_____ by next year.

4. She p_____his sleeves to get his attention.

5. There are countless _____(行星)moving around the sun in the space.