18.I________Helen since we________ at school together. (A) have known / were (B) know / were (C)knew / have been (D) know /is

20. Which sentence has a similar meaning? "The film started. Then we arrived at the cinema." (A) We arrived at the cincma. Then the film started. (B) When we had arrived at the cincma, the film had started. (C) When we had arrived at the cinema, the film started. (D) When we arrived at the cinema, the film had already started.