a) It's seven o'clock
b) It's a quarter past two in the afternoon.
Or
It's fifteen minutes past two in the afternoon.
c) It's twenty minutes past nine in the morning.
d) It's a half past 11 in the morning.
Or
It's thirty minutes past 11 in the morning.
e) It's twenty five minutes past 5 in the afternoon.
f) It's a quarter to 4 in the night.
Or
It's fifteen minutes to 4 in the night.