1. Nam spends three days finishing this book.
-> It takes Nam three days to finish this book.
2. My sisters spent two years to improve her English 
-> It took My sisters two years to improve her English 
3. It takes one hour to fly from HN to HCM
-> Hoa spends one hour flying from HN to HCM
4. It took us one hour to cook dinner.
-> We spent one hour cooking dinner.
5. Hoa was late because of her tiredness.
-> Because of her tiredness, she was late
6. He gets bad mark because of his laziness.
-> Because of his laziness, He gets bad mark