_ it goes on, hour ________hour.

Believe it or not，my sister and I are twins—Oh，you must have had the case________you were taken for your sister

The poor student works hard during this holiday _______ he’ll be able to get enough money for the next term.

It was 1969___ the American astronautssucceeded in landing on the moon.

I heard the alarm ringing all the morning____ something very urgent happened