请问 placed under the authority of the sth.还有,apply the directive given by sth.（职位名称）有时嘛意思?

Litter-baskets have been placed under the trees汉语意思 请问 placed under the authority of the sth.还有,apply the directive given by sth.（职位名称）有时嘛意思? we have placed litter-baskets under the threes改成被动句 litter baskets have been placed under the trees为什么不用has Litter baskets have been placed under the trees,but people still throw their rubbish everywhereeverywhere为什么加在最后 litter baskets have been placed under the trees 这句话是被动语态 求变成主动语态. 英语时态问题 关于以下这段话的填词Someone drawing water and my teacher placed my hand under the spout.As the cool stream gushed over one hand she spelled into the other the wordwater全文的时态是一般过去时.请问为什么 英语翻译Finding of a survey of Systems magazine subscribers:Thirty percent of all merchandise orders placed by subscribers in response to advertisements in the magazine last year were placed by subscribers under age thirty-five.Finding of a surve 请问：to meet the new demands being placed upon us studying at higher level怎么解释 Litter baskets have been placed under the trees,but people still throw their rubbish everywhere.throw为什么用现在时不是用过去的时态 Litter baskets have been placed under the trees,but people still throw their rubbish everywhere.时间副词still为什么放在throw前? the point of the screw has to be placed in the center of the cork.the point of the screw has to be placed in the center of the cork and turned into the cork under slight pressure.the screw should not be pulled through the cork,as parts of the cork co under the under the under the under the under the under the