_________ I reached the station when the train left.

• কোনো বাক্যে hardly had থাকলে, hardly had যুক্ত অংশটি past perfect tense এ হয়  ও verb এর past participle form হয় এবং hardly had এর পরবর্তী clause টি শুরু করতে হয় when দিয়ে এবং বাকি অংশ টুকু past indefinite tense এ হয়।
structure: Hardly had + sub + verb এর past participle form + When + past indefinite tense.

• প্রশ্নে উল্লেখিত অপশন অনুযায়ী,
- No sooner had হবে না কারন no sooner had..than  হয়।
- Scarcely had .... when হলেও প্রশ্নে  has দেয়া আছে তাই অশুদ্ধ। 
- সুতরাং সঠিক উত্তর - Hardly had

Complete sentence: Hardly had I reached the station when the train left.

• মনে রাখা জরুরি, no sooner...than, scarcely had..when, hardly had...when এভাবে আসে। 
- যেমন:
- No sooner had the thief seen the police than he ran away.
- Hardly had I reached the station when the train came.
- Scarcely had we reached the station, when the train left.