Ex2
1 Hydroelectric power plants are usually built on rivers.
2 I think that generator shaft is connected to the turbine.
Ex3
1 Nick noticed that everybody was looking at him.
Who noticed that everybody was looking at him?
What did Nick notice?
Nick noticed that everybody was looking at him, didn't he?
Did Nick notice that everybody was looking at him?
2 Sam drank a cup of coffee last morning.
Did Sam drink a cup of coffee last morning?
What did Sam drink last morning?
Sam drank a cup of coffee or a cup of tea last morning?
Sam drank a cup of coffee , didn't he?
Ex 4
1 Is George writing a composition or a report now ?
2 Today she has taken some books from the library.
3 The weather next week will be sunny with warm winds.