It is fairly common in Africa for _____ a group of musicians surrounded by others who also join in the performance.

The time and effort he has devoted during the past few years ______ trees in that remote area is now considered to be of great value.

The place is worth _________.  

   Finally they managed to find a path _______.

In the reading room, we found her____ at a desk, with her attention____ on a book.