pin down

• We were all pinned down by enemy fire .
  我们都被敌人的火力压制住了。
• She is a difficult person to pin down .
  她这人行事、说话没个准儿。
• He was pinned down by his attackers .
  袭击他的人把他按住了。
• It was difficult for me to pin down the subject .
  对我来说，要弄清楚这个问题很困难。
• The identity of each sex is not so easy to pin down .
  确定男女各自的特征并不那么容易。
• To pin down the size of an orbital, we take a contour surface .
  为束缚住轨道的大小，我们取一等值面。
• He is as slippery as an eel and simply refuses to be pinned down on anything .
  他很圆滑，什么事情都不肯承担责任。
• The task of their regiment was to pin down one of the flanks of the invading army .
  他们团的任务是牵制侵略军的侧翼。
• They plan further work in the area to try to pin down the factors responsible .
  他们打算在这一地区再做些工作以期确证这些起作用的因素。
• It is never possible nowadays to pin down any date within a year or two .
  要把任何日期确定下来，误差不出一两年，在当今的时世里，是永远办不到的。