As they- … the thieves broke into the house

Analyze the question The sentence is: "As they __ the thieves broke into the house." The verb "broke" is in the simple past tense. We need a verb form that fits with it and shows what was going on when the thieves broke in.

Explain the concept When one action interrupts another action that was already in progress in the past, we use:

• Past continuous (was/were + -ing) for the longer, background action
• Simple past for the shorter action that interrupts it

Example: While I was reading, the light went off.

Test each option

• A. had slept is the past perfect. It means the sleeping was finished before the thieves came, which doesn't fit "as" (meaning "at the same time as").
• B. are sleeping is the present continuous. It cannot go with "broke," which is past.
• C. have been sleeping is the present perfect continuous. It is also linked to the present, so the tenses clash.
• D. were sleeping is the past continuous. The sleeping was in progress when the thieves broke in. This fits.

Answer: The complete sentence is: *"As they were sleeping, the thieves broke into the house.

Exam tip: When you see "as" or "while" followed by a blank, and the other verb is in the simple past, look for the past continuous (was/were + -ing). The pattern is: past continuous (long action) + simple past (short interrupting action).