When, that time とき

If you don't know when to say something, you will never say it!

Using とき toki - at the time when...

With a noun add a の

[Looking at a photo]
私は学生のときにはとても若かったね。
watashi wa gakusei no toki ni wa totemo wakakatta ne. [looking at a photo] When I was a student, I was very young, wasn't I?

And with verbs...

simple past
フロリダに行ったときにこれを買いました。
furorida ni itta toki ni kore wo kaimashita. When I went to Florida, I bought this.

non-past
フロリダに行くときはおみやげを買います。
furorida ni iku toki wa omiyage wo kaimasu. When I go to Florida, I will buy souvenirs.

continuing
寝るときいつも布団で寝ます。
neru toki itsumo futon de nemasu. When I sleep, I always sleep on a futon.

For more information on time related words, click here