Help with the use of these words

can someone explain me the difference use among
these word?
時点
時
時期
頃
and among these
以前
前
thank you

時点 is used to refer to "point in time..." quite specific reference in time. Often used to refer to a specific time in the past.
- Nihon ni kita jiten de, Tomu wa nihongo wo mattaku shiranakatta. (As of the time when Tom came to Japan, he knew no Japanese at all.)

時 is more general "time," "time when..."
- Nihon ni kuru toki niwa, zehi watashi ni renraku wo kudasai. (WHen you come to Japan, please let me know.)

時期 refers to a bit longer time frame, time period,
- "Golden week" no ato no jiki wa, ryokou ni ii jiki desu. (The time after golden week is a good time (period) to travel.)

頃 can be used in the same way as 時期 "around the time of..."
- Sakura ga saku koro/jiki ga suki desu. (I love the time when the cheery blossoms bloom.)
頃 can also be used to mean "around..." "approximately..."
- 3-ji goro ni kite kudasai. (Please come around 3 o'clock.)


以前
- Izen o-ai shimashita ka? (Have I met you before? = prior to now)

前
- Jugyou no mae ni watashi no tokoro ni kite kudadai. (Please come to me before the class.)

thank you ^^