two_obstructions_有道手机词典

1.The trick is that two of the three slits are blocked by obstructions that can only be seen by looking in a mirror that reflects a backward view of what's inside the box.
问题难在这三道叉中有两道是被堵着的，只能通过镜子看盒子里面的倒影才能看出来。
dict.yoduao.com
2.For longer paths, detailed path surveys may be required to determine that there are no topographic or man-made obstructions blocking the line of sight between the two facilities.
对于长距离路径，则必须仔细勘查两个设施问的路径，确保在视距以内没有地形上或人为的障碍物。
dict.yoduao.com