Next practice your gn's and gl's. Then work on your r's and o's and double consonants. You can easily make more exercises of this sort for one another until you're able to switch from singular to plural or vice versa without consulting these pages. Actually, I'm going to save verbs for later, and turn to adjectives. Adjectives must be made to agree with the nouns they modify.
Adjectives can precede or follow nouns in a sentence.
More often they should follow.