0 In #1, the verb is in the passive voice, the past perfect tense. In the active voice, it would be 01font 00The gas explosion had blown out all the shop's windows. 02font 02br 02br 00In #2, 01font 00had02font 00 is the (whole) verb and 01font 00blown out02font 00 is a past participle used as an adjective.
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