Great work!

"Of" and your its features. What do you think about it?

    Notes: "Of" is a third person object, therefore "its" and not "yours."

One of the things I have been studying for the past few days

    Notes: "Have been" is correct, but one needs to use the "present perfect continuous" verb tense - "have been VERB-ing." This is used for something you have been doing continuously in the past and are still doing now.

    You can say "yesterday and today" but "the past two days" or "the past few days" is more fluid English. 

This preposition is the connection of the connects nouns making indicating a sense of the "belongs" "belonging" or as associated an association with quantity. Like there For example, next the following sentences: 

    Notes: In general, you are using noun phrases when they should be simple present tense verbs. "Is the connection of" can be substituted more simply with "connects."

The word "of" attaching attaches a noun to your its "owner" : The broken leg of the chair / The chair is the owner of the broken leg broked. (or, the leg that has been broken).

    Notes: Instead of the gerund "-ing" form, using the present tense, "attaches." Normally, we would just use the past participle "broken," but in this case, you can also describe what has happened to the leg, i.e., it "has/had been broken."

The word "of" supporting supports the numbers to your representation represented/indicated: Three (3) of the ducks were saved to from the fire of in the forest today this morning by the firefighters!

    Notes: You could also say: Three of the ducks were saved from the forest fire.

    Prepositions fixed. The ducks were saved. From what? The fire. Where was the fire? In the forest. By whom? The firefighters.

    You also don't need "today" because "this morning" already implies that it was today. 

Hope this helps! Good job!