unproductive的例句（unproductive在句子中的用法）

• To prospect for ( oil, for example ) in an area supposed to be unproductive. 盲目开掘在认为资源不足的地区盲目找 ( 如油 )
• One quarter of the country is reckoned as unproductive. 该国四分之一的土地被认为是不毛之地.
• I've had a very unproductive day. 我这一天什么事都没干成。
• ...increasingly unproductive land. 越来越贫瘠的土地
• Research workers are well aware that much of their time and effort is unproductive. 研究人员很清楚，他们的很多时间和精力全都是白费。