Using the waterfall development approach leads to lots of partially done work, because a lot of time is spent upfront in elaborating requirements and in design.
使用瀑布开发方法将会产生大量部分完成的工作，因为大量的时间会花在改善需求和设计之上。
2
High school students' lack of a historical knowledge base can partially be explained by the decrease in class time spent on social studies at the elementary level.
高中生缺少基础的历史知识总体上是因为他们花更少的时间在学习基本社会学科上。
3
Today, my brother's best friend spent the night and was changing with the door partially open.