—She ________ be. She ________ be missing her grandma who has Alzheimer's.
A:can't; must
B:mustn't; can
C:shouldn't; should
D:can't; would
如果x=3,y=2是二元一次方程ax﹣by﹣5=0的一个解,则3a﹣2b﹣1=____.