at the time of...

time of..., time for...

a female given name

time

at the critical moment

one day

a visit by a student's guardians to observe the class

in class

one, 1 / the first in order, foremost / the beginning / the best / a kind of; one of something / (card games) an ace / unity / the bottom string of a shamisen or other Japanese musical instrument

a hendecagon