SB 12.3.17

yugāni yuga-dharmāṁś ca
 mānaṁ pralaya-kalpayoḥ
kālasyeśvara-rūpasya
 gatiṁ viṣṇor mahātmanaḥ
Synonyms: 
yugāni — the ages of the universal history; yuga-dharmān — the special qualities of each age; ca — and; mānam — the measurement; pralaya — of annihilation; kalpayoḥ — and of universal maintenance; kālasya — of time; īśvara-rūpasya — the representation of the Personality of Godhead; gatim — the movement; viṣṇoḥ — of Lord Viṣṇu; mahā-ātmanaḥ — the Supreme Soul.
Translation: 
Please explain the different ages of universal history, the special qualities of each age, the duration of cosmic maintenance and destruction, and the movement of time, which is the direct representation of the Supreme Soul, the Personality of Godhead, Lord Viṣṇu.