7. Choose the correct answer. He wants to be ... actor.

The word "actor" starts with a vowel sound. Therefore, the indefinite article "an" should be used before it. The correct sentence is: He wants to be an actor.Step 1: Identify the word following the blank: "actor".
Step 2: Determine if "actor" starts with a vowel or consonant sound. It starts with a vowel sound.
Step 3: Choose the appropriate indefinite article. "An" is used before words starting with a vowel sound.