帮忙翻一下

原文：xx的截面大致呈“一”形，yy的截面大致呈“Ω”形。
译文：the section of xx is substantially straight shape, and the section of yy is substantially omega shape

想请问大家：

（1）上面的译文有误吗？

（2）为什么校对时后半句会给改成 the section of yy is substantially in a omega shape呢？如果有误，既然后半句改了，为什么前半句不改？

（3）类似于“A是L形”或“A呈L形”的表达应该是怎么样的？

译文中应保留“Ω”。
a omega shape--an Ω shape
the section -- the cross section

the cross section of xx has a substantially straight shape, and the cross section of yy has a substantially Ω shape

be of xx shape  be xx shaped