Used to indicate that something has not happened up to the present time.

अभी तक

English Usage: She has not called me yet.

Hindi Usage: उसने मुझे अभी तक नहीं बुलाया।

still; at this time

अब तक

English Usage: She hasn't finished her homework yet.

Hindi Usage: उसने अभी तक अपना होमवर्क खत्म नहीं किया।

Up to this time; until now.

इस समय तक

English Usage: I haven't eaten yet.

Hindi Usage: मैंने अभी तक कुछ नहीं खाया।

To this day; up to the present moment.

आज तक; वर्तमान क्षण तक।

English Usage: He is still waiting for her reply.

Hindi Usage: वह अभी भी उसका जवाब का इंतजार कर रहा है।