Grammar of すぐ医者に連れていこう

Question

I'm learning japanese on my own and face a sentence below.

この子、熱が高くてすごくつらそうだよ。 "すぐ医者に連れていこう。"

What i don't understand is the grammar in the last sentence. It seems that the book uses a Ving format. it's strange for me as i believe that "すぐ医者に連れこう" should also works here.

Can anyone explain why the book uses this sentence structure？ is the one i modified above still correct?

Answer 1

連れていこう is the volitional form of 連れていく. 連れていく means "to take (someone)(to somewhere)", and is made of the te-form of the verb 連れる ("accompany") + a subsidiary verb いく(行く) ("go").

「すぐ医者に連れていこう。」
"Let's take him/her to a doctor at once."

(連れこう is not a correct conjugation.)