He talks as if he __ everything

1. had known
2. knows
3. is knowing
4. Try your self

Answer: Try your self

Explanation: Note: As if (যেন) যুক্ত প্রথম close টি present indefinite tense হলে দ্বিতীয় close টি past indefinite tense হয়। Know (জানা) এর past form হলো knew যা অপশনে নেই।