英语简单语法题请高手给我解释下,这三道该选什么,选的理由是什么,小的谢谢你们了32. John said he’d be

英语简单语法题
请高手给我解释下,这三道该选什么,选的理由是什么,小的谢谢你们了
32. John said he’d been working in the office for an hour, _____ was true.
A. he B. this C. which D. who
31. —I drove to Zhuhai for the air show last week.
—Is that ________ you had a few days off?
A. why B. when C. what D. where
29.Though _______money, his parents managed to send him to university.
A. lacked B. lacking of C. lacking D. lacked in