Complete the following sentences as required (根据所给要求完成句子) :
1.People save water by taking a shower instead of a bath.(对划线部分提问)
________ ________people save water?
2.We use water to cook food. (对划线部分提问)
________ do we use water to________?
3.Whales are larger than any other animal on the Earth. (保持句意基本不变)
Whales are________ ________animals on the Earth.
4.Mr. Smith stayed at home last night. He didn't go shopping. (保持句意基本不变)
Mr. Smith stayed at home________ ________going shopping last night.
5.it, paper, reusing, save, can, people, by (连词成句) 
___________________________________
6.John can hardly understand Russian. (改为反意疑问句)
John can hardly understand Russian, ________ ________?
7.What a hot day today! (保持句意基本不变)
________ ________ it is today!
8.The Red Cross has helped the homeless people in the floods four times since last year. (对划线部分提问)
________ ________times has the Red Cross helped the homeless people in the floods since last year?