at Easter
復活祭の期間に
at eight (o'clock) on the dot ＝on the dot of eight (o'clock)
きっかり８時に
at every (possible) opportunity
あらゆる機会を捕らえて
at every step
ひと足ごとに
at eye level
目の高さに
at [above, below] eye level
目の高さ［より上，より下］に
at fifteen hundred hours
午後３時に
at first [last]
最初に［最後に］
at first glance
一見（して）
At first I had difficulty (in) telling one student from another.
初めは学生の顔を見分けるのに苦労した
