The visitors were surprised to see so many buildings going up at the same time.为什么用going up形式
问题描述：
The visitors were surprised to see so many buildings going up at the same time.
为什么用going up形式
答
表示现在进行时，看见一种状态。
答
The visitors were surprised to see so many buildings going up at the same time.参观者惊奇地看到,许多建筑物在同一时期拔地而起.see .sb do /doing do 原形表示看到全过程,doing 表示看的时候,“正在做”；显然...