• It's a quarter to six.
• It's a quarter past six.

• It's a quarter past two.
• It's a quarter to three.

• It's half past nine.
• It's half past ten.

• It's a quarter to two.
• It's a quarter past two.

• It's half past seven.
• It's half to eight.

• It's a quarter to three.
• It's a quarter past three.

• It's nine o'clock.
• It's twenty-one o'clock.

• It's a quarter past twelve.
• It's a quarter to one.

• It's eleven o'clock.
• It's twelve o'clock.

• It's ten to six.
• It's ten past six.