N4
と
If, When, Whenever, And, [Conditional]
甘いものをいっぱい食べると、太る。
If you eat a lot of sweet things, you will gain weight.
Explanation
「と」 has 3 uses
1Whenever, always
When the first happens, the second always follows: laws of nature, habits, or how a machine works: 「このボタンを押すと、お湯が出ます」 press this button and hot water comes out.
勉強をすると、テストは簡単になる。
If you study, tests become easy.
甘いものをいっぱい食べると、太る。
If you eat a lot of sweet things, you will gain weight.
2Giving directions
Says what you'll find if you go a certain way: 「右へ曲がると、駅があります」 turn right and you'll find the station.
この道をまっすぐ行くと、右に銀行があります。
Go straight down this road and you'll see a bank on the right.
二つ目の角を左に曲がると、駅が見えます。
Turn left at the second corner and you'll see the station.
3And found that
After doing something you discover something; the second half is past tense: 「家に帰ると、手紙が届いていた」 when I got home, a letter had arrived.
家に帰ると、母が来ていた。
When I got home, my mother had come over.
朝起きると、外が真っ白だった。
When I woke up in the morning, everything outside was white.