Question word ka or mo

A. In the conversation below nani ka means "something" or "anything" and nani
means "what."
Example
A : Kesa nani ka tabemashita ka.
"Did you eat anything this morning?"
B : Hai.
"Yes, I did."
A : Nani o tabemashita ka.
"What did you eat?"
B : Pan o tabemashita.
"I ate some bread."

In the first sentence, A wants to know whether B ate something this morning or not, so A uses nani ka instead of nani o. B needs not refer to the thing he ate in
his answer. In the second sentence, A wants to know what B ate, and A uses nani o. When question words such as nani, dare, doko, etc. are followed by the particle
ka, their meanings change. Notice how the meanings of the question words change by the addition of ka.

Examples
nani "what" - nani ka "something" or "anything"
dare "who" - dare ka "someone"or"anyone"
doko "where" - doko ka "somewhere"or"anywhere"
Question words with ka can be used in affirmative sentences or in interrogative sentences. They can be followed by Group 1 particles.

Examples
1. Dare ka kimashita.
"Someone came."
2. Nani ka nomimashita ka.
"Did you drink anything?"
3. Doko ka de koohii o nomimashita ka.
"Did you drink coffee somewhere?"
4. Dare ka ni shookai shimashita ka.
"Did you introduce him to someone?"

B. Question words like dare "who," doko "where," etc. can also be followed by the particle mo.

Examples
1. Dare mo kimasen deshita.
"Nobody came here."
2. Nani mo yomimasen deshita.
"I didn't read anything."

A question word + mo before a negative predicate means "nobody," "nothing," "nowhere,"etc. Some question words { mo before an affirmative predicate have an all-inclusive meaning, "always." "everyone" and "both."
*Table of the meaning of question words { mo construction*

Question word {mo {Negative {Affirmative

dare "who" dare mo "nobody" *
nani "what" nani mo "nothing" *
doko "where" doko mo "nowhere" "everywhere"
itsu "when" itsu mo "never" "always"
dore "which" dore mo "none" "everything"
dochira "which" dochira mo "neither one" "both"

Remember that the particle mo replaces particles ga and o, but follows other
Group 1 particles.

(See Lesson 1, NOTES ON CONVERSATIONAL GRAMMAR II.)

Examples
1. A : Dare ka kimashita ka.
"Did anyone come here?"
B : Dare mo kimasen deshita.
"Nobody came."
2. A : Doko e ikimashita ka.
"Where did you go?"
B : Doko e mo ikimasen deshita.
"I didn't go anywhere."
3. Itsu mo shinbun o yomimasu.
"Someone* always reads a newspaper."
4. Dochira mo tabemasu.
"Someone* will eat both of them."
(*"Someone" may be the speaker.)