关于名词加不定式的独立主格结构？

我们经常看到这样的例子，如下
If time permits, I'll go there tomorrow.
=Time permitting, I'll go there tomorrow.
那么既然条件状语从句中用了现在分词，保持了时态上的主将从现用法。那么问题来了，下面这个句子也是相当于条件状语从句哇，只不过花，草，树跟plant是被动的关系，那么这里为什么不保持主将从现了呢？怎么主句是将来，从句也是将来捏？
Many trees, flowers, and grass to be planted, our newly-built school will look even more beautiful. 
种上许多的树、花和草后，我们新建的学校看上去将更美。
重点就是，为什么不是Many trees, flowers, and grass being planted,用现在分词的被动一般式，让这个独立主格保持一个现在时，构成主将从现？
(Source: Zhihu)

(answered by: alexcwlin; edited by: Adam Lam)

Let me analyse the three sentences for you grammatically:

1.      If time permits, I’ll go there tomorrow.

“If” here is a Conjunction (more specially Subordinating Conjunction) similar to “and”, “or” , “until”, “provided”, etc.
It links two clauses together which, in this case, are “time permits, and “I’ll go there tomorrow”.
The clause “If time permits” is also called Adverbial Clause of Condition 条件状语从句which explains the circumstance (i.e., “time permits) under which the action in the main clause (i.e. “I’ll go there tomorrow”) will take place.

2.       Time permitting, I'll go there tomorrow.

“Time permitting” is an Present Participle Adverbial Clause which modifies the action of the main clause “go there tomorrow” by stating a situation of “Time permitting”.

3.      Many trees, flowers, and grass to be planted, our newly-built school will look even more beautiful.

Let me tell you that this sentence is not good English.

I search “Many trees, flowers, and grass to be planted” and it seems only Chinese websites publish this sentence in its exactness. It seems this is grammatically incorrect Chinese English.

The correct way of phrasing this sentence is:

a.       Provided more trees, flowers and grass are planted, our newly-built school would look even more beautiful.

b.      Once the project on planting more trees, flowers and grass are completed, our newly-built school will look even more beautiful.

c.       We need many trees, flowers and grass to be planted so that our newly-built school would look even more beautiful.