题目
When Tom arrived, he learned the TV play ________ for half an hour.
A.
had begun
B.
had been on
C.
had set off
D.
had started
知识点：初中英语知识点》动词》动词时态》过去完成时###牛津上海版（2008）》九年级第一学期》Module 2 Computers vs humans》Unit 4 Computers###牛津深圳版（广州沈阳通用）》八年级上册》Module 2 Science and technology》Unit 3 Computers###章节：Module 2