Question about SV number agreement for phrases

I subscribed in e-gmat verbal online. In their course, there are things that are always considered as singular when they are subjects such as:
- phrases and clauses
- collective nouns. (team, department, class, etc..)
- pronouns ending with -thing, -body, -ever, -one.
-each.

thank you aditya8062 for your reply,

As for my example, Is "rising inventory" consider as a phrase?? rising is an adjective as you mentioned. I wanted to ensure that the rule is always applicable that phrases and clauses when they are subjects act as singulars!

By 'phrases as subjects', they probably mean cases like these:

Taking our Great Pyrenees for a walk wears me out.

Everything that looks like that is singular. For instance, this is wrong: Taking our dogs for walks wear me out.

Even though 'dogs' and 'walks' are obviously plural, the whole phrase is singular.

What you've got there ('rising inventories') is sometimes called a 'noun phrase', which might be the source of the confusion. Noun phrases just consist of a noun plus the modifiers that modify it. They can be either singular or plural, depending on whether the noun is singular or plural. Here, 'rising' isn't being used as a verb, it's being used as an adjective which modifies 'inventories'.

Interestingly, the following sentence would be technically correct to the best of my knowledge, although it is a bit clunky and lacks concision.

The rising of inventories leads to production cutbacks.

Note the singular verb, 'leads'.