1. We had a great time in Hong Kong last summer. (改为同义句) We _____ _____ in Hong Kong last summer. 2. To understand what he is saying is too difficult. (同义句) _____ _____ too difficult to understand what he is saying. 3. The children have never seen an Indian film, _____ _____? (完成反意疑问句) 4. He says the bus has already gone. (把主句变为一般过去时态) He _____ the bus _____ already gone. 5. Chinese people invented the abacus in the sixth century. (改为被动语态) The abacus _____ _____ in the sixth century _____ Chinese people.