– Is that man Mr. Green?
– It _____ be him. He has gone to Paris on business.
A:may
B:must
C:can't
D:shouldn't
等差数列an中,若a4+a6+a8+a10+a12=120,则a9-13a11的值是 ( )
选出画线部分发音不同的一项。 ( )