How about joining us in the game?— I’m sorry.I have an urgent matter to ________.[ ]

hool shop, customers are mainly students, is closed for the holidays.

(2014·宝鸡三检)By the time the girl comes back to life，scientists probably________a cure for this incurable disease

The teacher spoke very slowly ____the students could understand everythinghe was saying.

d have helped him out, totell the truth, I _____ too busy.