______, I would have called her.

Third conditional এর নিয়মানুযায়ী, 
- principal clause এ would have/could have/might have + verb এর past participle থাকলে if clause টি past perfect হয়।
- যেহেতু, প্রশ্নে উল্লিখিত বাক্যে main clause এ subject (I) + would have + verb এর past participle আছে তাই If clause টিতে, subject + past perfect (had +seen) হয়েছে।

Complete Sentence - If Rina had seen me, I would have called her.

• একটি Conditional sentence  এ দুটি অংশ থাকে।
- 1. Condition বা শর্ত  
- 2. Consequence বা ফলাফল। 

• There are four types of Conditionals:
1. The Zero Conditionals
2. The First Conditionals
3. The Second Conditionals and
4. The Third Conditionals

এ ধরনের বাক্যগুলোর সাধারণ structure হলো:
• Zero Conditional = If + Present + Present (shows scientific and general truth)
• 1st Conditional = If + Present + Future
• 2nd Conditional = If + Past Simple + Future in Past (S + would/might/could + Base Form of the Verb)
• 3rd Conditional = If + Past Perfect (had +V3) + Perfect Modal (S + would have/could have/might have + V3)