These are the most common words in English, ranked in frequency order. The first 25 make up about a third of all printed material. The first 100 make up about half of all written material, and the first 300 make up about 65 percent of all written material. Is it any wonder that all students must learn to recognize these words instantly and to spell them correctly also.

 

 

After the hardening treatment is applied, steel is often harder than needed and is too brittle for most practical uses. Also, severe internal stresses are set up during the rapid cooling from the hardening tempera­ture. To relieve the internal stresses and reduce brittle­ness, you should temper the steel after it is hardened. Tempering consists of heating the steel to a specific temperature (below its hardening temperature), holding it at that temperature for the required length of time, and then cooling it, usually instill air. The resultant strength, hardness, and ductility depend on the temperature to which the steel is heated during the tempering process.