The reason why they__leave wasn't explained to us 中间的那哥空应该填哪

The reason why they__leave wasn't explained to us 中间的那哥空应该填哪 The reason why they__leave wasn't explained to us 中间的哪个空应该填哪 The reason why they had to leave wasn't explained to us.为什么用 They explained the reason to us why they had hated us before Wouldn't it be great if you explained the reason to us? the reason(why\which) he explained The reason why she failed the test was that she wasn't prepa The reason why she failed the test was that she wasn't p____ I don't quite know the reason _______ he explained to me There wasn't ___ in the room.So it wasn't ___ for us to work The way that/which/不填 he explained to us was quite simple. the reason why i didn't go to meet