分类：教育/科学-学习帮助
问题：单项选择9.iknowallaboutthefilmbecaus 
9. i know all about the film because i _______  twice.a. saw b. had seen c. have been seeing d. have seen
回答：d. 现在完成时，强调对现在的影响---我非常了解这部电影