Change active to passive: Do the experts regards this compound as hazardous?

Explanation:

Step 1: Identify the tense

Active sentence:
“Do the experts regard this compound as hazardous?”

• This is in Simple Present Tense (Interrogative)

Step 2: Rule for Passive (Simple Present Interrogative)

Active:
Do/Does + subject + base verb + object?

Passive:
Is/Are + object + past participle (V3) + by + subject?

Step 3: Apply the rule

• Subject → the experts
• Object → this compound
• Verb → regard → regarded (V3)

So,
👉 Is this compound regarded as hazardous by the experts?

❌ Why other options are wrong:

1. Has this compound been regarded…
   → Present Perfect tense (wrong tense)
2. Is this compound being regarded…
   → Present Continuous (wrong tense)
3. Was this compound regarded…
   → Past tense (wrong tense)

Extra Facts:

1. “Regard as” structure remains unchanged in passive
   • Active: They regard him as a genius
   • Passive: He is regarded as a genius
2. Helping verb changes according to tense
   • Present → is/am/are
   • Past → was/were
   • Perfect → has/have been
3. In interrogative passive sentences, the helping verb comes first:
   • Is the work done?
   • Are the results announced?

Final Answer:

Is this compound regarded as hazardous by the experts?