—I don't know if it ____ tomorrow.
—Well, if it ____, I won't go out with you.
A:will rain; will rain
B:rains; rains
C:rains; will rain
D:will rain; rains
在等差数列an中,已知a1+a2+a3+a4+a5=20,那么a3=
下列各组词语中,有两个错别字的一组是( )