How to define “common core” in English?

How to define “common core” in English?

Normally， at the elementary and low intermediate stages of English learning， the learner is mainly exposed to the “common core” English， which refers to those basic English items that appear in most or all varieties of English. Even though one can identify many varieties in a language， there are a lot in common among them. This “common core” English can be applied in most of the language use situations and is generally inoffensive， if it is used by a learner of English as a foreign language.评分参考：每小题10分。答案全面，要点无遗漏，语言正确，10分；答案基本正确，遗漏个别要点，语言错误较少，得6-9分；答案遗漏若干要点，语言错误较多，得3-5分；答案要点不清，与问题联系不密切，语言不连贯，且有严重错误，得1-2分。答案与问题无联系或无答案，0分。