Use of English PRO

Researchers (0) HAVE different theories concerning the origin of the word. Some say that it (1) ............ first used in English in 1827 and is adapted (2) ............ the Aboriginal word wo-mur-rang, which dates (3) ............ even earlier. Non-returning boomerangs (or shaunies) were traditionally used (4) ............ hunting weapons, while (5) ............ returning boomerang has mainly been used for leisure activities. Australian Aboriginal boomerangs have been made (6) ............ thousands of years and continue to be produced in the traditional way. Sourced from bent tree roots, hunters would remove a part of the tree without causing too (7) ............ damage. A stone-headed axe would be used to painstakingly cut the selected tree root from the tree. To make the piece of wood return, you need to carve its blades at specific angles. These aerodynamic techniques create a flat airfoil, (8) ............ is designed to spin about an axis perpendicular to the direction of its flight — hence flying in a circle and eventually coming back to the thrower.