Which words in the תּוֹרָה tell us it is a מִצְוָה to say שְׁמַע in the evening?
וְדִּבַּרְתָּ בָּם ... וּבְשָׁכְבְךָ
What is the earliest time you can say קְרִיאַת שְׁמַע at night?
When three stars come out
May a כּהן who was טַמֵא and was טוֹבֵל in a מִקְוֶה eat תּרוּמה right away?
No, he has to wait until 3 starts come out