1.主语 + 连系动词 + 表语 (S+V+P) 此结构不可用被动语态。 (正) The flowers smell sweet. (误) The flowers are smelt sweet. 2.主语 + 不及物动词 (S+V) 此结构不可变被动语态。 (正) An accident happened last night. (误) An accident was happened last night...