By now = ইতিমধ্যে/ এতক্ষণে (Already অর্থে)

তোমার ইতিমধ্যে এটা মুখস্ত করে ফেলার কথা ছিল। = You were supposed to have memorized this by now.

সে নিশ্চয়ই এতক্ষণে (তার) বাড়ি পৌঁছে গেছে। = He must have reached his home by now. =  He must have arrived at his home by now.

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