For diagramming practice, here are some sentences that may use subjects, verbs, adjectives, adverbs, and conjunctions. (P.S. These are difficult; work slowly.)

1. Act quickly. [solution]
2. The car stalls frequently. [solution]
3. Both Dexter and his friend competed relentlessly. [solution]
4. He studied slowly but surely. [solution]
5. The student wrote flawlessly but talked incessantly. [solution]
6. The wise professor thought very deeply. [solution]