The intake and exhaust valves alternately and selectively opens and closes, and simultaneously openes during a valve overlap period, in synchronism with a rotation of a crankshaft to open the passages to the combustion chamber, wherein said apparatus controls a valve timing of the intake valve and the valve timing of {HEAD ~ the exhaust valve} in {TAIL ~ accordance} with a running condition of the engine 
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The intake and exhaust valves alternately and selectively opens and closes , and simultaneously openes during a valve overlap period , in synchronism with a rotation of a crankshaft to open the passages to the combustion chamber , wherein said apparatus controls a valve timing of the intake valve and the valve timing of { HEAD ~ the exhaust valve } in { TAIL ~ accordance } with a running condition of the engine
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