A:will arrive
B:arrived
C:arrive
D:would arrive
下列各组词语中,没有错别字的一组是( )
—Excuse me,may I take a seat here? 一____________.The man on the seat has left.
若a,b,c为实数,且a<b<0 ,则下列命题正确的是( )
①硝酸铵和水;②铁和稀硫酸;③固体氢氧化钠和水;④生石灰和水;⑤石灰石和稀盐酸.