非谓语动词与从句的相互转换一、如何把复合句改为简单句呢?首先,分清主从复合句,先要取消从句,一般要把引导从句的连词去掉。例如:When he was waiting for the bus, he saw a dog.Waiting for the bus, he saw a dog.其次,如果从句的谓语动词是主动式,就要把谓语动词改为现在分词;如果从句的谓语动词是被动式就要把谓语动词改为过去分词;并且要注意时态的变化。例如:1. After he had finished his homework , he went home.Having finished his homework, he went home.2. Because I have promised to meet my friend at the airport, I cant accept your invitation.Having promised to meet my friend at the airport, I can