-bestruckdumb;allatsea;bewide-eyedandnotmakeasound;besoawed(atthesightof)thatonecouldn'tspeak;(He)isflabbergastedandhasnothingtosay.;makesb.openhiseyes;One'smouthopenswidewithsurprise.;gape;stareat...,tongue-tied;staredumbfounded;staretongue-tied;wide-eyedandtongue-tied