Sentence:  He can ( 1 ) point his car resolutely at the invading fender and force the other driver back into Lane A ; ( 2 ) slow down and permit the ambivalent driver to change lanes ; or ( 3 ) alternately accelerate and decelerate , thus <WSD>keeping</WSD> the first driver guessing as to his intentions , thereby making a fascinating sport of the whole affair . 
Meaning of the word marked with <WSD> tags:  keep in a certain state, position, or activity; e.g., "keep clean"