十五: 表示方位概念.如:close to,next to
I don't like wool next to my skin.
十六: 表示依靠或借助,如:resort to,turn to,appeal to
He usually appeals to arms to settle the territory dispute.
十七: 表示有关注,关于: as to,with regard to
十八: 表示关注或重视,如:pay attention to,attach to
We should attach primary importance to job training.
十九: 表示依据或是根据,如:according to,in proportion to
According to today's newspaper,the match will be postponed.
The lending countries subscribe towards capital stock in proportion to heir economic importance.
二十: 表示应该或必须含义的句式, 如:
It's time to get up.
We are supposed to get here at seven.
It's up to this country to ban nuclear weapons.