1. An English input method, comprising: receiving, by an electronic equipment, an input English character string having an original length, wherein the electronic equipment includes an input device and runs an input application program compatible with the input device for obtaining user inputs; calculating, by the electronic equipment, a target length based on the original length of the English character string; looking up, by the electronic equipment, a target English word having a length between the original length and the target length; automatically calculating, by the electronic equipment, a longest common length between the target English word and the English character string by using a dynamic programming method, where the common length refers to a length of identical letters between the target English word and the input English character string, so that when the English character string inputted by the user skips one or more characters from the target English word, the longest common length allows the target English word to be identified; and returning, by the electronic equipment, the target English word when the longest common length is equal to N times the target length so that the target English word is a correctly-spelled word to tolerate user mistakes in the input English character string, where N is a positive number less than or equal to 1.