onto 到…上。 get onto a horse 骑到马上。 ★ 1.美国一般与前置词 into 一样,作一个词处理。 英国则以分写作 on to 为普遍;美国口语中可作为 on 或 to 的代用语。 如:They finally got onto (=on) the bus. The crowd got onto (=to) the street. 2.须注意勿与各有独立意义的 on 和 to 相混淆,如:They drove on to the town.
Let x is the limit of the inverse system . suppose each projection is an open and onto map . and x is - paracompact . if each x is normal mesocompact , then x is mesocompact . moreover , we obtain the analogous result for hereditarily normal and hereditarily mesocompact properties | = ,假设每个投射_ : x x _是开的且到上的。 x是-仿紧的,如果每个x _为正规中紧的,则x是正规中紧的,进一步得到关于遗传正规且遗传中紧空间的结论。