passengers have to --across---改cross-- the lin by footbridge.
need l feed the dog three times a day -----yes you--- need 改must---
you had better not----- to 去掉to-----go out because it is very hot outside now.
may l watch the football match before finishing my home work----no you ----may not--改musn‘t---
----Shall we have a meeting tomorrow?
---Ok,but we should be in a big meeting-room.