The Certificates in English Language Skills (CELS) are a set of standard tests that allow you to test in one or more of the four language skills, or combine tests at different levels. Tests are available at three levels: GELS Higher, CELS Vantage and GELS Preliminary (初步的). So, if, for example, you are particularly good at reading but have difficulty in speaking English, you could take a CELS Higher test in Reading, CELS Vantage tests in Listening and Writing, and, for Speaking, a CELS Pre liminary test. Or you could decide not to take a speaking test at all. Those are linked(连接) to other Cambridge ESOL examination levels, such as the First Certificate in English. CELS are also accredited (公认) as part of the UK National Qualifications Framework. For more information on these, you can get a copy Of the GELS Handbook from Cambridge ESOL Chinese website. You can also visit www. alte. org for an overview of the 'Can Do' statements ,which specify what you are expected to be able to do at each level. It is implied in the passage that ______.