lt's nine o'clock mike must ____（go）to bed.

lt's nine o'clock mike must ____（go）to bed.
lt's nine o'clock mike must ____（go）to bed.

lt's nine o'clock mike must ____（go）to bed.
must是情态动词,情态动词后加动词原形,所以填go

就填 go

goes,第三人称单数