Talking About What You Did in Japan

How to form past tense sentences:
します [shimasu] I do → しました [shimashita] I did

見ました [mimashita]
I saw it.

• 見ます [mimasu] I see it.
• 見ました [mimashita] I saw it.

飲みました [nomimashita]
I drank it.

• 飲みます [nomimasu] I drink it.
• 飲みました [nomimashita] I drank it.

週末は何をしましたか [shūmatsu wa nani o shimashita ka]
What did you do over the weekend?

• 週末 [shūmatsu] means "weekend"
• 何をしますか [nani o shimasu ka] What do you do?
• 何をしましたか [nani o shimashita ka] What did you do?

勉強しました [benkyōshimashita]
I studied.

• 勉強します [benkyōshimasu] I study.
• 勉強しました [benkyōshimashita] I studied.

• A: 昨日は何をしましたか
  What did you do yesterday?
• B: 昨日は勉強しました [kinō wa benkyōshimashita]
  I studied yesterday.
• A: あの、先週は何をしましたか
  Hmm.. What did you do last week?
• B: 先週は映画を見ました [senshū wa eiga o mimashita]
  I watched a movie last week.
• A: どこで映画を見ましたか
  Where did you watch the movie?
• B: 映画館で見ました [eigakan de mimashita]
  I watched it at the movie theater.