There are a few reasons for that the foremost is that the suit, and not the pockets, is the subject of the sentence. Another factor to consider, is the usage, I find a grammar book apart from usage to be incomplete. Lastly, word order differs from language so do not think that we can use the same order in translation. In German the verb is often at the end of the sentence, and one would sound like Yoda to do the same in English.
Because costume is a masculine noun.
- du (+ masculine noun)
- de la (+ feminine noun)
- de l’ (when noun begins with vowel sound)
There are multiple correct answers that do not include "of." If you are using word tiles, it doesn't allow for all possible translations. If you prefer to enter your own response, you can change the settings by clicking on the keyboard icon and get writing exercises rather than tap tile exercises.