When you have the broad match modifiers, your ads will be better positioned to appear when searches contain the key words one has marked with a plus sign or close variations of the words. The matching of key words are usually being utilized by companies that set out to sell an array of products to a large customer group. These companies can avoid the use phrases or matching words when the key words in their ads are better structured with the broad modifiers.
Progressive Tax Structure In this system, taxpayers making more money pay higher tax rates than those making less money (your example) . The US uses this system.