In Japanese, one common way to give reasons or explain why something happens is by using 〜て after verbs and い-adjectives, or the particle で foafterr nouns and な-adjectives.
You've already learned how to use で after nouns for giving reasons.
I had a cold, so I stayed home from school. | 風邪 で、 学校 を 休みました。kaze de, gakkou o yasumimashita. |
It works the same for な-adjectives. Just place the particle で after them.
The room is clean, so it feels nice. | 部屋 が きれい で、 気持ち が いい です。heya ga kirei de, kimochi ga ii desu. |
The station is close and convenient, so I decided to live here. | 駅 が 近くて 便利 で、 ここ に 住むこと に しました。eki ga chikakute benri de, koko ni sumukoto ni shimashita. |
To give a reason with い-adjectives, you change the final い to くて.
This shop is cheap, so it’s popular. | この 店 は 安くて、 人気 が あります。kono mise wa yasukute, ninki ga arimasu. |
It was cold outside, so I wore a coat. | 外 が 寒くて、 コート を 着ました。soto ga samukute, kooto o kimashita. |
When using verbs, the 〜て form is often used to connect actions or to explain the cause or reason for a result. The 〜て form links clauses and can imply because or since in many cases.
I caught a cold, so I took a rest. | 風邪 を 引いて、 休みました。kaze o hiite, yasumimashita. |
I walked for a long time, so I got tired. | 長い 時間 歩いて、 疲れました。nagai jikan aruite, tsukaremashita. |
In many cases, 〜て for verbs and い-adjectives and で for nouns and na-adjectives can function similarly to and in Japanese, linking clauses together. However, whether these forms are interpreted as expressing a reason (i.e., because) or simply as connecting two actions (i.e., and) depends on the context of the sentence. So you'll need to infer from the context whether 〜て or で is being used to mean and (sequential actions) or because (cause and effect).