てforms for joining sentences
Just like using the てform to join to verbs, it can also be used to combine adjectives and nouns.
The てform of an いadjective is formed by substituting くて for the final い.
The てform of a なadjective and a noun+です is formed by adding で to the base or the noun.
い adjective: やすい→ やすくて
irregular: いい → よくて
な adjective: げんき（な）→ げんきで
noun + です： にほんじんです → にほんじんで
あのみせのたべものはやすくて、おいしいです。
The food at that restaurant is inexpensive and delicious.
やましたせんせいはにほんじんで、よんじゅっさいぐらいです。
Prof. Yamashita is a Japanese and he is about forty years old.