

My sister is a junior in high school.
[ˈmaɪ ˈsɪstər ˈɪz ə ˈdʒunjər ˈɪn ˈhaɪ ˈskul.]
The juniors are taking their big exams next week.
[ðə ˈdʒunjərz ər ˈteɪkɪŋ ðər ˈbɪɡ ɪɡˈzæmz ˈnɛkst ˈwik.]
Are you a junior or a sophomore this year?
[ər ju ə ˈdʒunjər ɔr ə ˈsɑfˌmɔr ˈðɪs ˈjɪr?]
"junior" is in the lesson "Education" (Level 35), along with 10 other useful words. LinDuo has 180 topic lessons like this one, 2,375 words in total. Every word has an illustration, a transcription and pronunciation in a female and a male voice. Just 10–15 minutes a day is enough to learn them all. Free, and works offline.