請問這個句子，那個才是動詞和請分析句子結構是怎樣?

句子中所提及的 restrictions 限制 --- 只管制土地用途而未嘗管控土地開發(區)的密度和容積

Until 1973 ,
在1973年以前，

the planning restrictions that did exist
確實存在的規劃限制，

were confined to controlling the use that land could be put to with no attempt to control the density or volume of development.
只局限於管制土地用途而未嘗管控土地開發的密度和容積。

Rewrite the sentence in other way with similar meaning:
There were planning restrictions before 1973, but they were only confined to controlling the utilization of land rather than trying to control the density or volume of development as well.

那個才是動詞和請分析句子結構是怎樣?
main verb = were confined (passive voice)
subject (object of transitive verb "confine") = the planning restrictions "that did exist" (relative clause modifying "restrictions")
prepositional phrases:- (adverbials)
1. until 1973
2. to controlling the use "that land could be put to" (relative clause modifying "use")
3. with no attempt to control the density or volume of development.

Until 1973
直到1973年，

the planning restrictions (that did exist) were confined to controlling the use (that land could be put to)
既行的都市計劃管制侷限於管控土地如何利用，
(that...) 括號內都是形容詞子句，可刪去。

with no attempt to control the density or volume of development.
未曾試圖就開發密度或總量上，予以控制。
(with 前加個comma 會更清楚易讀)


...that land could be put to use
put to use 的意思是 utilize，"開發利用"

Until 1973----prepositional phrase
the planning restriction (that did exist)---------S + relative cl.quali."restriction" ;could be omitted
were confined-----V , plural of was ; conditional ; in the form of the past tense of" be" ; passive voice ;
to controlling the user-------prep phrase(adv.)
(that land could be put to)--------adj cl.could be omitted;=be put to use.
with no attempt to control the density or volumn of development-----------co-ord.adj phr.
It means simply:_
Land use were confined to a plan, not volume.
管控土地利用;
未管控數量密度..