The questions were quite complex and required in depth knowledge of English Grammar. The interviewer was highly knowledgeable and demanded explanations for every point. Overall the interview helped me understand where my Grammar stands.

They asked very standard questions about previous employment. They also have a pre-test where they ask grammar questions, which is a little challenging, so revise basic grammar rules before taking the test. The people are friendly and don't ask questions that are very difficult, so just be prepared to answer questions about your employment background.