Hardly had we reached school ____________.

Negative word + Auxiliary verb + Subject + main verb + extension.
No sooner had ….. than, scarcely had …….. when, hardly had …….. before এর প্রথম অংশ Past Perfect and Verb এর Past Participle হয় এবং ২য় অংশে Past Indefinite হয় । উল্লেখ্য, no sooner.......than, scarcely......when, hardly........ when আসে- এ বিষয়টি মাথায় রাখতে হবে । যেমনঃ No sooner had we reached the station than the train left, Hardly had the train stopped before we got down, Scarcely had we started when it began to rain.