Pre-University education in the UK lasts for 12 years, last 2 years of which are specialized. Russian (Ukrainian, Kazakhstan) the Certificate of complete secondary education is not sufficient for University entrance in the UK. Students from the CIS countries before applying for admission to Oxford, you must pass the level exams A-Level or International Baccalaureate (IB). Will also fit the American SAT or ACT.
To prepare for these exams either after finishing the Russian high school (or a school in another country) or received school education in the UK:
The first year of a bachelor degree, completed in the University at home can be enough to apply.