1. Ms Hoa has taught English since 2000.
2. It is very difficult but interesting to learn Japanese.
3. 3D printing allows us / people to make three-dimensional objects.
4. Driverless cars can be useful for / in reducing road traffic accidents.
5. We should avoid opening the door at night / leaving the door open at night.
6. Easy communication is one of the benefits / advantages of the Internet.
7. The invention of the email enables us to exchange information conveniently.
8. 3D printing is used to reduce production costs / for reducing production costs / in the reduction of production costs.