"He can read the time on his little alarm clock."
Translation:Il sait lire l'heure sur son petit réveil.
"L'heure" is the time of day, "le temps" is the time of year, season, weather, etc. If it can be shown on a clock, it's "l'heure", otherwise it's "le temps".
Threw me off by using savoir. Why didn't they just equate it to He knows how to read...
without context it should be an accepted alternative: "il peut lire...."
"Il sait lire l' heure sur son réveil". was not accepted. Yet, I see "réveil" can mean alarm clock. Reported.