妈妈每天在家做饭特别的辛苦，特别是在切洋葱时会留眼泪，原因时洋葱中含有刺激眼睛的物质，那么这些物质存在于洋葱细胞的______中．

The manager ______ the worker how to do it, or the accident couldn’t have happened.

A．couldn’t have told

B．ought to tell

C．could have told

D．mustn’t have told