1. Some fashion designers have printed lines of poetry on the "ao dai", so it looks modern

→ Because____some fashion designers have printed lines of poetry on the " ao dai ", it looks modern________

2. Poets have mentioned the "ao dai" in poems for centuries 
→ The "ao dai"___has been mentioned in poems by poets for centuries________
3. The design and material used for men were different from those used for women 
→ The design and material used for men were not___the same as the design and material used for women_______
4. My father stopped smoking two years ago 
→ My father hasn't___smoked for 2 years_________
5. Let's use electricity economically

→ Why____don't we use electricity economically ?________
6. Someone will blow a whistle if there is an emergency
→ A whistle__will be blown if there is an emergency_________
7. They have worked in that factory for ten years
→ They began___working in that factory 10 years ago__________
8. The boy is sorry for being late 
→ He wishes___he weren't late_________
9. People say that the soil here is very rich 
→ The soil here______is said to be very rich_____
10. Helen started to learn Chinese in 2000 
→ Helen has been learning chinese since 2000______

`1`. Because some fashion designers have printed lines of poetry on the "ao dai", it looks modern.

`2`. The "ao dai" has been mentioned in poems by poets for centuries.

`3`. The design and material used for men were not the same as those used for women.

`4`. My father hasn't smoked for two years.

`5`. Why don't we use electricity economically?

`6`. A whistle will be blown if there is an emergency.

`7`. They began working in that factory ten years ago.

`8`. He wishes he weren't late.

`9`. The soil here is said to be very rich.

`10`. Helen has been learning chinese since 2000.