Question about とき

Question

I am working on the みんなの日本語　標準問題集　初級 I Lesson 23.

There is a question related to the usage of とき。

パスポートを（なくします　ー＞＿＿＿＿＿＿＿＿）とき、どうしますか。

けさここへ　（来ます　ー＞＿＿＿＿＿＿＿＿＿）とき、駅で新聞を買いました。

The answers are:

パスポートを（なくした）とき、どうしますか。

けさここへ（くる）とき、駅で新聞を買いました。

I cannot understand:

1. Why the first sentence uses past tense, because I think it asks a general question about what shall be done when passport is lost.

2. Why the second sentence uses dictionary form rather than きた。I think the action "come" has completed when the speaker speaks this.

Please help. Thank you very much.

Answer 1

1. As you said, it is a general question. Since it is asking what would you do when you lose the passport (the action is completed in the future), past tense is used.
   If it is a repeated action, present tense is used. 本を読むとき、あなたはどこで読むのが好きですか？(When you read books, where do you like to read?)
   
   
2. This is a quite tricky one.
   
   a. This morning, you went to A and on the way to A, you bought a newspaper at the station. Now, you are at A and you tell to your friend: 今朝ここへ(ここ means A)来るとき、駅で新聞を買いました
   
   b. Let's think a little bit tricky situation. Imagine place A is a large building that has a station and your office (In Japan, this kind of large building is called 駅ビル). Now you are walking from B to somewhere with your friend and now passing by A. You tell your friend: 今朝ここへ来たとき、駅で新聞を買いました。
   
   In situation b, you are not talking about the action on the way to A, but the action after you arrived at A. That's why using past tense is acceptable. I would say situation b is quite rare.