在他三十多岁时 in his thirties

我在大三时 My junior year ; I'm at three o'clock

在他大三时 In his three o'clock ; Him three o'clock ; In his junior year

我在这三个小时了 In three hours ; I'm here for three hours

在三个小时之内 In less than three hours ; In three hours

在三年时间里 In Three Years Time

在他三十几岁时 While in his thirties

在三个小时 At three hours over time

在大学三年级时 At the time of junior