plane cross-section assumption

例句：

1. 1. The engineer made a precise cross-section assumption to design the new bridge.
   工程师为了设计这座新桥，做了精确的截面假设。
2. 2. The scientist conducted an experiment to test the hypothesis that the temperature would increase due to the cross-section assumption.
   科学家进行了实验来测试这个假设：由于截面假设，温度会上升。
3. 3. The architect used the cross-section assumption to calculate the weight of the building'sstructure.
   建筑师利用截面假设来计算建筑物结构的重力。