Final answer:
Sentences a and d are in passive voice because the subjects are being acted upon, while b and c are in active voice since the subjects perform the action. Understanding and effectively using both voices can improve writing clarity and impact.
Step-by-step explanation:
The concept of voice in English grammar--specifically active voice and passive voice--determines whether the subject of a sentence performs the action (active) or receives the action (passive).
Let's analyze the provided sentences:
The clothing was wrinkled after being left in the dryer for too long. - Passive
I burned the toast. - Active
Marian scraped her knee when she fell off her bike. - Active
The drink was spilled all over the floor. - Passive
In summary:
a. Passive
b. Active
c. Active
d. Passive
By understanding the differences, you can choose the voice that best matches your writing goal, whether it's to emphasize the action's performer or to focus on the action itself.