1

我不知道

wǒbùzhīdào

I don't know.

2

他

tā

(third-person singular) (since the early 20th century, usu. male) he; him; his (bound form) other; another; some other (as in 他日 tārì and 他人 tārén)

3

在

zài

to exist; to be alive (of sb or sth) to be (located) at (used before a verb to indicate an action in progress)

=4

哪

nǎ

how which

=4

哪

na

(emphatic sentence-final particle, used instead of 啊 a after a word ending in "n")

=4

哪

né

used in 哪吒 Nézhā Taiwan pr. nuó

=4

哪

něi

which? (interrogative, followed by classifier or numeral-classifier)