Coldir cuses therteriesround the hert to constrict.become rigidB．contrctC．closeColdir cuses therteriesround the hert to constrict.become rigid B．contrct C．close D．die

Experts wrn tht globl wrming will cuse drmtic climte chnges, including more ________ floodsExperts wrn tht globl wrming will cuse drmtic climte chnges, including more ________ floods, het wvesnd droughts. [ ]usul B．frequent C．ordinry D．common

Studies conducted during the 1970s on prents－children reltionship indicted tht ______.Studies conducted during the 1970s on prents-children reltionship indicted tht ______.dolescence did not cuses much troubles clinicinsnd theorists hd stted B．children’sggressivenessnd rebelliousness were growing C．children-prents reltionship ws declining D．teengers becme even morebhorrent of their prents