Mr jiang's mother was very pleased with the robot. She is telling Mr jiang on the phone about her life with the robot. Rewrite her sentences with to-infinitives.
1 I was so forgetful that I didn't lock the door last night.
1 I was so forgetful that I didn't lock the door last night.
答案：I was too forgetful to lock the door last night.
解析：“so...that...”结构（如此……以至于……），当从句为否定时，可转换为“too...to...”（太……而不能……），“so forgetful that I didn't lock”即“too forgetful to lock”。
解析：“so...that...”结构（如此……以至于……），当从句为否定时，可转换为“too...to...”（太……而不能……），“so forgetful that I didn't lock”即“too forgetful to lock”。
2 The robot was so careful that it reminded me of this.
答案：The robot was careful enough to remind me of this.
解析：“so...that...”结构，当从句表示肯定意义时，可转换为“adj. + enough + to do sth.”，“so careful that it reminded”即“careful enough to remind”。
解析：“so...that...”结构，当从句表示肯定意义时，可转换为“adj. + enough + to do sth.”，“so careful that it reminded”即“careful enough to remind”。
3 I was so weak that I couldn't go up and down the stairs often.
答案：I was too weak to go up and down the stairs often.
解析：“so...that...”否定结构转换为“too...to...”，“so weak that I couldn't go”即“too weak to go”。
解析：“so...that...”否定结构转换为“too...to...”，“so weak that I couldn't go”即“too weak to go”。
4 The robot was so kind that it bought me everything I needed.
答案：The robot was kind enough to buy me everything I needed.
解析：“so...that...”肯定结构转换为“adj. + enough + to do sth.”，“so kind that it bought”即“kind enough to buy”。
解析：“so...that...”肯定结构转换为“adj. + enough + to do sth.”，“so kind that it bought”即“kind enough to buy”。
5 Sometimes I took a walk with it so that I could have a better sleep.
答案：Sometimes I took a walk with it in order to have a better sleep.
解析：“so that”引导目的状语从句，可转换为“in order to + 动词原形”，表示目的，“so that I could have”即“in order to have”。
解析：“so that”引导目的状语从句，可转换为“in order to + 动词原形”，表示目的，“so that I could have”即“in order to have”。