As soon as Betty .............................................. the door, the burglar alarm ...

★ Past Perfect and Past Perfect Continuous Tense

As soon as Betty ………………………………………. the door, the burglar alarm went off. (open)

A. opened

B. had opened

C. was opening

D. had opended

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Bruno and Marcela met at a medical assembly, which Marcela ______ _______ ________ for a long time.

A. was attending

B. has been attending

C. have been attending

D. had been attending