arrow

(as) straight as an arrow:
1. in a straight line or direction
2. a straight arrow is someone who is very traditional, honest, and moral

The oldest evidence of stone-tipped projectiles [发射物], which may or may not have been propelled [推进] by a bow, dating to about 64,000 years ago, were found in Sibudu Cave, current South Africa. Arrowheads made from animal bones have been discovered in the Fa Hien Cave in Sri Lanka [斯里兰卡] which are also the oldest evidence for the use of arrows outside of Africa dating to about 48,000 years ago. The oldest evidence of the use of bows to shoot arrows dates to about 10,000 years ago; They had shallow grooves [沟槽纹] on the base, indicating that they were shot from a bow.

Arrow sizes vary greatly across cultures, ranging from eighteen inches to six feet (45 cm to 150 cm). However, most modern arrows are 75 cm (30 in) to 96 cm (38 in) in length.

The shaft [杆] is the primary structural element of the arrow, to which the other components are attached. Traditional arrow shafts are made from strong, lightweight wood, bamboo or reeds, while modern shafts may be made from aluminium, carbon fibre reinforced plastic, or a combination of materials.

The arrowhead or projectile point is the primary functional part of the arrow, and plays the largest role in determining its purpose. Some arrows may simply use a sharpened tip of the solid shaft, but it is far more common for separate arrowheads to be made, usually from metal, horn, or some other hard material.

Fletchings are found at the back of the arrow and act as airfoils to provide a small amount of force used to stabilize the flight of the arrow. They are designed to keep the arrow pointed in the direction of travel by strongly damping down any tendency to pitch or yaw.

Fletchings are traditionally made from feathers (often from a goose or turkey) bound to the arrow's shaft, but are now often made of plastic (known as "vanes").

Artisans who make arrows by hand are known as "fletchers," a word related to the French word for arrow, flèche. This is the same derivation as the verb "fletch," meaning to provide an arrow with its feathers. Glue and thread are the traditional methods of attaching fletchings.

六级/考研单词: arrow, propel, bow, cave, shallow, groove, shot, shaft, component, bamboo, aluminum, carbon, fibre, reinforce, horn, damp, seldom, goose, turkey, bind, derive, verb, thread