英语求助 为什么要加 that of ?

iyxx37

涂色部分为什么不是直接  than outer ring ? 为什么要加 that of  ?




Due to the tight fits, the inner ring of the bearing is
expanded and the outer ring with the roller-and-cage
assembly is contracted. Thus the radial clearance of the
bearing is reduced after mounting. It is further re
duced during operation as the operating temperature
of the inner ring is higher than that of the outer ring.
For this reason bearings with an increased radial clear
ance (C4...C5) are mounted.

浅风无影

因为than 前后应该都是温度，没有that 指代Temperature 就变成温度和ring比较了。

菜哥

that 代指温度，语法我讲不清楚，但我经常看到这个用法，背得多了，也能脱口而出。