"他参加的电影" 指的是某个人参与拍摄或表演的电影。在英文中，可以用 "films he has participated in" 或 "movies he has been in" 来表示。
下面是一些例句：
"John has been in many films throughout his career, including 'The Matrix' and 'Avatar.'" (约翰在他的职业生涯中参与了许多电影，包括《黑客帝国》和《阿凡达》。)
"Sally has participated in several independent films, as well as some mainstream productions." (萨莉参与了几部独立电影，也参与了一些主流制作。)
注意，如果你想表示某个人参与了某部电影的制作或表演，可以使用动词 "participate" 或 "be in"。但如果你想表示某个人是电影的观众，那么你可以使用动词 "watch" 或 "see"，例如：
"I watched 'Inception' last night." (我昨晚看了《盗梦空间》。)
"Have you seen 'The Shawshank Redemption' yet?" (你看过《肖申克的救赎》吗？)