I keep medicines on the top shelf, out of the children’s       .

The teacher has a(an) ___________ to get off topic; sometimes it is difficult for students to make out what he is saying.  

According to a UN report，one third of the world population have no    to clean drinking water and health care.

She went to the bookstore and bought       .

Due to the widespread________ of this medical technology, more diseases can be discovered and treated at an early stage.