以下是重构后的句子：
1. 他的房子是我童年时期唯一的固定居所。(原句翻译：His house was the only settled home I had as a child.)
2. 当动脉发生病变时，移植成为了唯一的治疗希望。(原句翻译：The arteries are diseased and a transplant is the only hope.)
3. 尽管鲁宾逊咖啡屋里的人正在逐渐减少，但这个过程并不迅速。(原句翻译：The crowd in Robinson's Coffee-House was thinning, but only by degrees.)
4. 对于可用水的总量，他们只有模糊的概念。(原句翻译：They have only a vague idea of the amount of water available.)
5. 在同一时间，我们在同一所学院就读，而那时这所学院只招男生。(原句翻译：We were in the same college, which was male-only at that time.)
