1. I don't know why tractors can't replace oxen (for ploughing) in some African countries.
2. The organization where I'm working is planning to set up a clinic in a remote area in Kenya to help improve the health condition of the children there.
3. The other day, the tailor received the new sewing machine donated by a charity.
4. This is a jar in which to store seeds.
5. Astronauts need to be trained for several hundred hours before going into space.