V.
1. I used to look after my younger brother when my parents went to work.
2 Bell demonstrated his invention to the public at countless exhibitions.
Vl.
1. Mark isn't old enough to ride his bike to school
2. We used to lid our houses with candles in the past.
3. It is dangerous to put a knife into an electrical socket.
4. They are going to participate in the festival in Hue next week.





