YOU SAID:
I don't know when he'll arrive.
INTO JAPANESE
彼がいつ到着するのか分からない。
BACK INTO ENGLISH
I don't know when he will arrive.
INTO JAPANESE
彼がいつ到着するのか正確にはわからない。
BACK INTO ENGLISH
I don't know exactly when he will arrive.
INTO JAPANESE
彼がいつ到着するのか正確にはわからない。
BACK INTO ENGLISH
I don't know exactly when he will arrive.
Come on, you can do better than that.